Author Topic: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack  (Read 40246 times)

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Offline nctnico

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I have been hunting for a 1GHz+ scope for over half a year. I prefered one which has a high enough samplerate to do this in a single shot. Ofcourse it is 'easy' to spend several $k on a Lecroy Wavepro 7000 series or something similar but I didn't want to spend that much and avoid too much overlap with the oscilloscopes I already have. The older Lecroy LC584 is also interesting and I nearly got one but the Ebay seller bailed out on me (I did got a refund though). I also looked at the Tektronix TDS694C and TDS784 but the problem with these scopes is that they are older than the Agilent 54835A, have an obsolete NVRAM (SRAM + battery) inside and need special calibration software. The 54835A OTOH can calibrate itself using the auxilary output so it doesn't depend on calibrations values or options stored in a NVRAM. Big plus! My main application for the 54835A is looking at high frequency signals (digital and analog). The 54835A has a maximum depth of 65kpts on 2 channels and 32kpts on 4 channels and no peak-detect. I guess that if you don't want to spend much then deep memory and peak-detect are out of the window. OTOH the 54835A has a lot of tools for signal analysis like FFT, color grading and stacked/chained math functions.

After some haggling and waiting I got this one from an Ebay seller called express_test:


First I would like to point to this nice page with a different repair job on a similar scope: http://www.dasarodesigns.com/projects/fixing-an-hp-agilent-54845a-infinium-oscilloscope/ It has many details on the circuits.

The most appearant problem is that it doesn't boot but otherwise it is a complete mistery. The upside is that the hard drive is detected which means it spins up and likely still has the software on it.

I opened it first to check whether all the wiring is connected and there are no potential safety issues.

Some pictures of the inside. First the part where the PC lives. Inside there is a VA503-A Super Socket 7 motherboard from FIC with an AMD K6-2 400MHz processor and 64MB of SDRAM memory.


The acquisition board is at the underside. This is also where most of the airflow is directed.


Time for firing it up for the first time. With a PS/s keyboard connected I got passed the BIOS error message and after a short while the firmware started. The scope runs on Windows 98 (first edition). After a quick check it turned out (only) channel 2 is not working. All in all the noise isn't as bad as I had expected seeing the two 120mm fans. The high pitched whining noise from the hard drive is way more irritating.

Time to take try and fix it
Changing the battery (which was empty) helped to get rid of the BIOS error and made the scope boot without needing to press a key. Note the bodge capacitor!


The first thing I wanted to try is to swap the attenuators. From the service manual I learned that the probe connector panel had to come off before the BNCs of the attenuators can be unbolted. Unfortunately this means peeling the sticker off before the screws which hold the panel can be reached. That didn't work out very well:



I think it will still look reasonable when put back together again.

Some further disassembly:



A spark plug socket for a socket wrench fits nicely on the BNC's nuts BTW.

After swapping the attenuators it turned out the problem still persisted. Not happy! In the next step I swapped the ADC hybrids between channel 1 and 2:



The ADC hybrids are connected to the board using some sort of socket with pogo-pins (spring loaded pins) which make contact between the ADC hybrid and the board. Ofcourse I cleaned everything with alcohol. Still no luck though. The problem moved with the ADC hybrid. In a final attempt to rule out any other problem I cross connected the attenuator outputs using SMA cables.


Still no go so the only conclusion is that the ADC hybrid which is now on channel 1 is broken. I managed to source a module for (what I think) is a reasonable price but I have not received it yet.

After this I ran a full diagnostic which also pointed to some errors in the trigger circuit. Maybe it has been damaged because a piece of shielding metal wasn't fixed to the frame. Here is a picture which shows the shied re-attached to the frame using some M3 screws:


When browsing on the hard drive I found an interesting help file: HP4XS.HLP . This seems to contain a partial guide to do component level diagnostics/repairs. Hopefully it is helpful if it turns out the trigger circuit is really defective.

Cleaning
With nothing else to do let's give the outside a thourough cleaning to get rid of the grease marks and sticker residu. Much better if I may so so:


Hard drive image
I have not been able to find any older versions of the software for this oscilloscope so I made a backup using Ghost. For this I needed to connect an extra hard drive. The problem is that there are no power extension leads to do this so I made one out of the wires from an old AT power supply. The VA503-A motherboard has both AT and ATX style power connectors and the AT one isn't used but suitable to drain some power from.

After this creating an image was easy.

Rubber fan mountings
The rubber fan mountings where completely perished and I have a bag of leftover cable glands.


I like to think this made an improvement.

Time for some uphacking!
I already knew from the service manual that the hardware for the 54835A, 54845A (1.5GHz 8Gs/s) and 54846A (2.25GHz / 8Gs/s) is exactly the same so there had to be some option strappings to set the model. Forum member Jwalling pointed me towards some resistors on the acquisition board which set the type of oscilloscope. The bad thing is that these resistors are on the solder side of the acquisition board so I had to take the entire board out.

The board is covered with a rubber-ish RF shielding slab.

After removing the RF shielding:


When glancing over the board something odd caught my eye and I had a WTF! moment:


This chip isn't attached to the board except with one leg! Some flux and solder fixed that but oddly enough it didn't seem to have any effect on the errors the self test showed.

Back to the uphacking part. I located several resistors and decided to attach some switches after a few futile attempts to change the resistors using SMT tweezers.



The scope software can be stopped using ctrl-alt-del which opens up the task manager on Win98 and restarted from the menu so testing all the combinations could be done quickly.
Code: [Select]
R3 R2 R1 R0
-  -  X  X  54835A
X  X  -  -  54845A

X = placed, - = open

I have not found the 54846A mode but I have not included R4 in my test because I didn't spot it when looking for potential candidates. For now I'm fine with the 54845A mode.

There where also two other things on my wishlist: more memory and a faster processor. Much to my surprise FIC still has an FTP server with documentation and BIOS files ftp://ftp.fic.com.tw/motherboard/. How cool is that? From the documentation I learned the maximum memory is 768MB divided over 3 modules of 256MB each. It also should support the AMD K6-3 450MHz processor which (ofcourse) is faster and according to legend among the fastest socket 7 processors ever made. So I went on Ebay and spend $18 +shipping on 3 256MB memory modules and $15 on an AMD K6-3 450MHz. The memory was advertised as new but I got 3 different modules and anti-static bags so I'm quite sure these are pulls. But hey, they where only $6 each. The biggest SDRAM module I had in my pile is 64MB so I guess back then 256MB ones would have been insanely expensive. The AMD K6-3 450MHz however did look brand new:



Installing the memory was straightforward. The processor proved more difficult. First of all I needed to dig up a Pentium-I cooler from my scrap heap because the original heatsink is glued onto the processor. Secondly with the new processor installed and setting the right core voltage & multiplier it wouldn't boot. Drats! After some Google-fu I found a forum message from the beginning of this millenium saying FIC has a beta BIOS version which supports the K6-3 450MHz. I found this in FIC's FTP server with version number JN4116. However the current BIOS version on the motherboard said JN4204 which I couldn't find in FIC's archive so this could be a special Agilent version. I also would expect version 4204 to be newer than 4116. I decided to give it a try and save the old version twice (and check!) before attempting to flash the BIOS with version 4116. End result: BIOS version 4116 works with the AMD K6-3 450MHz and so does the oscilloscope software! The performance increase (waveforms/s) is about 15%.

Running Windows XP
The PC part is powerful enough to run XP. There are three advantages of XP: it supports USB sticks, it runs the processor cooler and it can run the latest version of the software I found. Part of the process is also to install an SSD consisting of an mSata module in an mSata to 44pin IDE converter:

I also needed a CD-ROM drive so I threw that into the mix as well:


While doing this I ran into a problem. The XP installer would get either into a blue screen or it would not recognise the mSata drive. The first problem was caused by a slightly faulty CD-ROM drive the latter because the PCB which converts the 40 pin IDE into 44 pin IDE+power has been designed without any idea about signal integrity:


Using a UDMA IDE cable+seperate 40 to 44pin convert allowed XP to install so on to the software. Installing the software took a while and after installing it, it complained about needing a license. So I also installed the licensing server. After this the software starts but crashes because it can't find a DLL. Also the driver for the acquisition board is missing. I guess a seperate software package is needed which has the driver and a low level interface layer. I have not been able to locate either of those (except from an Ebay seller which asks nearly $500 for it). According to a post from Wuerstchenhund the new software is not a big improvement over the old software so I decided to go for plan B and use Win98 instead. So I saved an image from the XP install and copied the image from the original software onto the SSD.

Windows 98 and the original software seem to work just fine with the converter PCB in the middle so this is the final setup:

BTW: this picture shows another problem I didn't spot until I made this picture!

USB sticks & Win98
I still wanted to be able to use USB sticks to save screendumps and data to. Sure I could use the network for that but USB is easier. After some Googling I found this page http://www.technical-assistance.co.uk/kb/usbmsd98.php which has a software package to install USB stick support on Win98. After installing I had to re-install the driver for the USB sticks I had inserted earlier but after that it worked just fine.

Leaky capacitors!
This picture says it all:


This meant I had to dissasemble the PC part and thus take all the boards and the motherboard out:

I had some new low ESR capacitors lying around and for good measure I added a 4.7uf 100V ceramic.
After putting everything together the scope still worked so I guess the capacitor replacement went OK.

Time for some play
Let's try a 200MHz AM modulated signal first:


Add some color grading in the mix:


Let's try FFT and stacked math functions on a 200MHz FM modulated signal (+/-10MHz FM swing)

The yellow line is the base FFT trace. The green is the max hold and blue is the averaged FFT trace. I have not tried it but it should be possible to have more than one FFT trace.

I checked the risetime from a square wave. When the samplerate is 4Gs/s the (calculated) bandwidth is 1.1GHz. At 8Gs/s the bandwidth is 1.5GHz. Not bad!

What is left is to wait for the ADC hybrid to turn up and see which errors remain after I have fitted it. To be continued...
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 
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Offline alm

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #1 on: July 08, 2017, 03:44:58 pm »
Thanks for that write-up!

Weird that that loose logic IC did not give any self-test errors. Maybe it was just interfacing with the dead ADC module, and hence the failure was being hidden?

I am surprised that upgrading the CPU resulted in an increase in waveform/s. I would have expected that to be handled completely in hardware that writes directly to the screen (DMA).

So there is no difference in the calibration procedure for the various models? I could imagine the adjustments for front-end flatness etc might be different. Nice upgrade, anyway.

Now fingers crossed that replacing the hybrid will indeed fix all the errors. It seems likely, based on the tests that you have performed, but you never know until you try it. It could always be something obscure where one of the surrounding components is marginal, barely working with some hybrids and barely failing with others.
 
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Offline Tony_G

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #2 on: July 09, 2017, 12:24:13 am »
In case you need it I saved a copy of the software folders from the Keysight FTP Server (they went missing last time I checked there)

https://1drv.ms/f/s!Amqar8_XQ9Uzj6YhN1xHdM8tQdKMOA

TonyG
 
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Online TheSteve

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #3 on: July 09, 2017, 02:33:00 am »
Great post so far. You know I love a good bandwidth upgrade so I'm looking forward to the updates.  :-+
VE7FM
 

Offline Jwalling

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #4 on: July 09, 2017, 09:39:41 am »
When browsing on the hard drive I found an interesting help file: HP4XS.HLP . This seems to contain a partial guide to do component level diagnostics/repairs. Hopefully it is helpful if it turns out the trigger circuit is really defective.

Very nice find! I wish I knew about that file years ago!!
What on earth made you look through all the help files?

EDIT: I just took a look at some images I've saved off from this series of scopes. Given the same firmware revision, this help hp4xs.hlp file is the same one that's on the 54810A through 54825A scopes. There is also a hp1xs.hlp file, and I believe that this one is used for the lower end scopes up to the 54825A.
« Last Edit: July 09, 2017, 10:04:24 am by Jwalling »
Jay

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Offline nctnico

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #5 on: July 09, 2017, 10:06:46 am »
When browsing on the hard drive I found an interesting help file: HP4XS.HLP . This seems to contain a partial guide to do component level diagnostics/repairs. Hopefully it is helpful if it turns out the trigger circuit is really defective.
Very nice find! I wish I knew about that file years ago!!
What on earth made you look through all the help files?
Being bored for 5 minutes and dumb luck made me click that file ;)
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline nctnico

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #6 on: July 09, 2017, 10:26:58 am »
In case you need it I saved a copy of the software folders from the Keysight FTP Server (they went missing last time I checked there)

https://1drv.ms/f/s!Amqar8_XQ9Uzj6YhN1xHdM8tQdKMOA
Thank you! I'm downloading the archive right now. I found the FTP archives too and noticed the files where missing but I assumed my FTP clients where not compatible with the server.
« Last Edit: July 09, 2017, 11:31:30 am by nctnico »
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline nctnico

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #7 on: July 09, 2017, 02:09:57 pm »
Update: I managed to update the software to version 4.3 thanks to Tony_G's archive. I see FFT phase has been added to the math functions as well as other minor improvements.

Upgrading from a USB stick instead of the LS120 drive needed some hacking using a hex editor on the oscilloscope program. The upgrade process always loads the upgrade from drive a: and you can't set it look on a different drive  :palm: . With help of the hex editor I changed all path (not text) references to a: into e: where the USB stick sits. After that it would load the software from the USB stick and do the upgrade process. I'll have to do the same to go from 4.3 to 4.5.

According to the documentation 4.5 is an incomplete package and meant to be installed on top of 4.3. Since my scope ran version 3.72 it seemed wise to install 4.3 first and then 4.5.
« Last Edit: July 09, 2017, 02:15:20 pm by nctnico »
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline stj

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #8 on: July 09, 2017, 04:47:21 pm »
you cant use USB on the FIC VA503,
it has the first implementation - v1.0
1.0 is bugged and will not work right.
(hence USB v1.1)

stick a pci card in it for USB function.

one other thing about those boards, most have the pcb pads for a proper mini-din ps2 socket under the full-size din socket and mouse headers.
« Last Edit: July 09, 2017, 04:49:47 pm by stj »
 

Offline Jwalling

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #9 on: July 09, 2017, 04:54:05 pm »
you cant use USB on the FIC VA503,
it has the first implementation - v1.0
1.0 is bugged and will not work right.
(hence USB v1.1)

stick a pci card in it for USB function.

They work fine with thumb drives with the Win98 USB hack. I know because I've done it myself.
It's Win98 first edition that has the problem with USB storage.
Jay

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Offline stj

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #10 on: July 09, 2017, 05:20:03 pm »
no, your just getting lucky because your data packets over usb are short.
the via oppollo MVP3 chipset has buggy usb implementation - that's official.

i have that board in a tower - it served me 24/7 for very many years and still acts as a network backup unit.
there really isnt much i dont know about it.
inc the fact it can overclock the cpu at 125MHz if your ram is up to it. (7ns or faster)
 

Offline Jwalling

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #11 on: July 09, 2017, 05:31:19 pm »
no, your just getting lucky because your data packets over usb are short.
the via oppollo MVP3 chipset has buggy usb implementation - that's official.

i have that board in a tower - it served me 24/7 for very many years and still acts as a network backup unit.
there really isnt much i dont know about it.
inc the fact it can overclock the cpu at 125MHz if your ram is up to it. (7ns or faster)

One thing I do know: VIA chipsets were always  bug-ridden POS. In short, they suck! :--
I have a FIC VA-503 motherboard right now I could test with - how would I make the bug manifest itself?
Jay

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Offline stj

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #12 on: July 09, 2017, 05:38:18 pm »
transfer lots of data in a single pass.

writing a shitload of stuff to a usb key will often cause the interface to hang after while.
i imagine any streaming devices like tuners will cause absolute chaos.
btw, the first intel chipsets with usb 1.0 had the bug too - it was in the design spec they where supplied with!!!
oops!  :palm:
 

Offline lukier

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #13 on: July 09, 2017, 05:43:01 pm »
nctnico: is 54835A the same architecture as 54381D (https://www.eevblog.com/forum/testgear/agilent-54831d-modernising/)? I mean does it use the ancient C&T graphic card?

If yes then there should be still some, albeit limited, room for improvement (in the PC department), instead of relying on the Socket7 motherboard that I guess is not really good anymore (performance, bad caps).

LeCroy's are better in that respect, as they only use a single PCI card to communicate with the oscilloscope board so one can upgrade as far as Windows 7 32 bit can get (even i7 Haswell with PCIe to PCI adapter). Other connectivity is pretty standard, LVDS for the LCD (I've upgraded mine to XGA), standard signals for the CCFL inverter and, on WaveRunner 6K, the front panel is just a USB HID device (a bit problematic on newest hardware, doesn't like Intel root hubs, so one must use a separate USB controller).

Maybe, because of different PC integration architecture the CPU processing power is not as important as in LeCroy's case. Still, more modern CPU and motherboard with SATA and USB would be nice I guess. I have no idea how the Agilent software would react to upgraded PC internals though.
 

Offline Jwalling

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #14 on: July 09, 2017, 06:06:17 pm »
nctnico: is 54835A the same architecture as 54381D (https://www.eevblog.com/forum/testgear/agilent-54831d-modernising/)? I mean does it use the ancient C&T graphic card?

If yes then there should be still some, albeit limited, room for improvement (in the PC department), instead of relying on the Socket7 motherboard that I guess is not really good anymore (performance, bad caps).


Before anyone starts talking WinXP on the 54810A series.  ;)
The 54830/31/32A/D used 1GHz or 1.2 GHZ Pentium III processors on a newer platform without ISA slots. They did use the same C&T graphics driver chip, though. However, the ACQ controller is newer (In fact the older ACQ controller from the 54810A series is present but only used for power on functions, front panel control, and the scope's video frame buffer) I think upgrading to XP would be a problem as the driver for the ACQ controller would not want to talk to the old ACQ board.

EDIT: And I don't think the pin-out for the ribbon cable is the same anyway...

EDIT2: which wouldn't matter anyway. Duh. You'd have to find an XP driver for the OLD controller.

The picture shows the newer ACQ controller in red, the old one in blue

If one could find a newer motherboard (just to upgrade the hardware for performance) with an ISA slot (For GPIB functionality) it just might work.
« Last Edit: July 09, 2017, 06:19:22 pm by Jwalling »
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Offline Jwalling

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #15 on: July 09, 2017, 06:12:14 pm »
One other thing -  IME the FIC motherboard won't work with GB Ethernet cards for some reason either. I tried a Realtek 8169 based card which I had Win98 drivers for.
Jay

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Offline Jwalling

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #16 on: July 09, 2017, 06:43:53 pm »
Something I've always wondered, but have never figured out. What does the battery powered SRAM on the ACQ controller hold?

I've been too chicken to disconnect the battery from a working scope to find out... :scared:

Never seen one that was dead either.
Jay

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Offline nctnico

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #17 on: July 09, 2017, 06:59:02 pm »
nctnico: is 54835A the same architecture as 54381D (https://www.eevblog.com/forum/testgear/agilent-54831d-modernising/)? I mean does it use the ancient C&T graphic card?

If yes then there should be still some, albeit limited, room for improvement (in the PC department), instead of relying on the Socket7 motherboard that I guess is not really good anymore (performance, bad caps).
The 54835A uses a C&T CT5550 graphics card. I'm not a fan (understatement) of AMD and VIA but I have to assume HP/ Agilent did some reliability tests before deciding to use this particular motherboard for a high end oscilloscope. I actually found a service note from Agilent from 2005 which describes a recall to replace the existing motherboard with the VA503-A and put a VIN33 (latest hardware version) sticker on the back of the scope. I think upgrading the motherboard can be done but the acquisition and videocard will need a PCI slot. And there is also the limitation of the AT style keyboard connector in the casing and how much power can the power supply deliver? All in all there won't be many options to make the PC part much faster.

@stj: I'll keep an eye open for USB problems. So far USB sticks are working OK and if not then I'm quite sure I have a USB-PCI card somewhere in an old PC.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline lukier

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #18 on: July 09, 2017, 07:15:45 pm »
I think upgrading the motherboard can be done but the acquisition and videocard will need a PCI slot. And there is also the limitation of the AT style keyboard connector in the casing and how much power can the power supply deliver? All in all there won't be many options to make the PC part much faster.

There should be plenty of more modern options, there are Core2Quad motherboards featuring 2 PCI slots. You only have to be brave enough to take a metal nibbler and cut the ATX IO shield opening (I have no idea why Agilent decided to do their own cutouts, seems silly) :) Often newer processors have better performance/power consumption ratio so I wouldn't worry about the PSU that much (and you've gained some watts by going the SSD route, CD drive can be disconnected as well).

However, maybe Agilent software depends heavily on a particular motherboard and/or BIOS as is the case in some older Tek scopes (which are even worse as they use very custom form factor motherboard).
 

Offline free_electron

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #19 on: July 09, 2017, 07:17:48 pm »
no need to peel the front label off to remove that probe interface board.  from inside the scope : between bnc of channel2 and channel3 you will see 2 metal clips. simply press those and the netire pcb including the metal stiffner pops off. you don't need to muck with the screw nor destroy the front panel....


as for the battery ont he interface board : that holds the attenuator click count and the self diagnostic / calibration data. if that bettery goes empty simply rerun the diagnostic.

you can launch scope.exe using the service command  " scope.exe /service" that gives extra options in the self test menu where you can set attenuator click and othe roptions
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Any comments, or points of view expressed, are my own and not endorsed , induced or compensated by my employer(s).
 
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Offline stj

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #20 on: July 09, 2017, 07:20:34 pm »
there are 3 in the family,
the 503, the 503A and the 503+
i cant remember the differences,
but one has both AT & ATX power connectors and sockets for both 66MHz 72pin sims, and 100MHz sdr-dims.
(i have that model)
 

Offline nctnico

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #21 on: July 09, 2017, 09:32:11 pm »
no need to peel the front label off to remove that probe interface board.  from inside the scope : between bnc of channel2 and channel3 you will see 2 metal clips. simply press those and the netire pcb including the metal stiffner pops off. you don't need to muck with the screw nor destroy the front panel....
I looked again but with the attenuators fitted it is impossible to get to those clips. There is a square hole as well. Maybe that is to be used to push the probe connector panel out. BTW someone before me already peeled the sticker off in the places where it is mostly damaged. Maybe I can get things to improve by melting the glue a little bit.
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Offline Jwalling

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #22 on: July 09, 2017, 10:57:34 pm »
no need to peel the front label off to remove that probe interface board.  from inside the scope : between bnc of channel2 and channel3 you will see 2 metal clips. simply press those and the netire pcb including the metal stiffner pops off. you don't need to muck with the screw nor destroy the front panel....
I looked again but with the attenuators fitted it is impossible to get to those clips. There is a square hole as well. Maybe that is to be used to push the probe connector panel out. BTW someone before me already peeled the sticker off in the places where it is mostly damaged. Maybe I can get things to improve by melting the glue a little bit.

There is a little metal "nub" that you can push out from the inside with a small flat-blade screwdriver. I'd be surprised if there's no info about it in the service guide...
I'll take a picture tomorrow and post it.

Done. The metal nub is highlighted. It's right below the CH3 BNC.
Edit: Crap - that was the 54831B. I'll try again in a bit...

Here it is.
« Last Edit: July 10, 2017, 01:26:45 pm by Jwalling »
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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #23 on: July 10, 2017, 02:45:20 am »
Nice write up. Thank you.


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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #24 on: July 10, 2017, 09:50:33 am »
Nice write-up and pictures!  :-+

I have been hunting for a 1GHz+ scope for over half a year. I prefered one which has a high enough samplerate to do this in a single shot. Ofcourse it is 'easy' to spend several $k on a Lecroy Wavepro 7000 series or something similar but I didn't want to spend that much and avoid too much overlap with the oscilloscopes I already have. The older Lecroy LC584 is also interesting and I nearly got one but the Ebay seller bailed out on me (I did got a refund though).

Well that's bad. But there should be plenty of similar scopes on the market.

There recently was a WavePro 950 (1Ghz 16GSa/s) for less than £1k on ebay UK (maybe it still is) but I guess it depends on what you wanted to spend.

Quote
I also looked at the Tektronix TDS694C and TDS784 but the problem with these scopes is that they are older than the Agilent 54835A, have an obsolete NVRAM (SRAM + battery) inside and need special calibration software. The 54835A OTOH can calibrate itself using the auxilary output so it doesn't depend on calibrations values or options stored in a NVRAM. Big plus!

It's a nice feature, although most newer DSOs shouldn't show a noticeable parameter shift even more than a decade, unless something is broken.

Quote
My main application for the 54835A is looking at high frequency signals (digital and analog). The 54835A has a maximum depth of 65kpts on 2 channels and 32kpts on 4 channels and no peak-detect. I guess that if you don't want to spend much then deep memory and peak-detect are out of the window. OTOH the 54835A has a lot of tools for signal analysis like FFT, color grading and stacked/chained math functions.

Don't expect too much, especially on a Windows 98 unit. You get a bit more than with an older InfiniiVision scope, but it shows that these Infiniiums were HP's first attempts at doing a Windows scope. The 54835A was designed as a general purpose bench scope, not as an analysis scope, where its capabilities are more limited. The architecture is really super-slow, but the old Win9x models with Socket7 mobo even managed to strangulate this slow architecture through its even slower PC part (slow and buggy VIA chipset). Also, not all Win9x variants can be upgraded to XP, which is recommended so you can use the later software which contains more functions and lots of bug fixes.

Also, reliability wasn't exactly great on these Infiniiums. We had lots of them and lots of problems with dead ADC hybrids, acquisition board issues, trigger issues, issues with the interface card and dying PSUs. Agilent only really got a handle of that with the successor Infiniium DSO8000/DSO80000.

As other said upgrading isn't easy because of the different interface cards but frankly going beyond the K6-3 450MHz won't offer you much performance improvement as when you go to a P2 or faster the architecture becomes the limiting factor (and the Windows part is only used as display on these scopes). I'd still consider getting a P2 board with ISA slot to get rid of the buggy VIA chipset, though.

Depending on what you want to do, a DSO8104A (which with some patience can be found <$1500) might have been a better option (although even my DSO8064A's BW exceeds 1GHz), as it has a faster architecture without the antique C&T65500 secondary graphics adapter and hardware mixing, runs XP on a late P4 mainboard with PCIe, SATA and fast onboard gfx, is much more reliable, offers up to 128Mpts memory (unlockable via hack) and 32Mpts FFT, and even has Peak Detect which seems to be important for you. Also the XGA touch screen is a notable improvement over the VGA display of the 54800 Series, as traces look cleaner and you can get more information on the screen (although you probably still want to use a mouse).

« Last Edit: July 10, 2017, 09:56:00 am by Wuerstchenhund »
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Offline nctnico

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #25 on: July 10, 2017, 10:43:59 am »
Nice write-up and pictures!  :-+

I have been hunting for a 1GHz+ scope for over half a year. I prefered one which has a high enough samplerate to do this in a single shot. Ofcourse it is 'easy' to spend several $k on a Lecroy Wavepro 7000 series or something similar but I didn't want to spend that much and avoid too much overlap with the oscilloscopes I already have. The older Lecroy LC584 is also interesting and I nearly got one but the Ebay seller bailed out on me (I did got a refund though).
Well that's bad. But there should be plenty of similar scopes on the market.

There recently was a WavePro 950 (1Ghz 16GSa/s) for less than £1k on ebay UK (maybe it still is) but I guess it depends on what you wanted to spend.
That was one of the big questions. I have compiled a rather long list with scopes which included the Wavepro 900 series (preferably a 960) and even the Wavepro 7000 but in the end I had to be sensible and look at what unique features an older >1GHz scope would really add to my lab and the answer was: bandwidth and a noisy dog house. So I opted for a model which was relatively small, light and cheap. Spending more would mean buying features I already have. The 54835A is not going to be my daily use scope. I will only switch it on if I need the bandwidth.
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Offline Wuerstchenhund

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #26 on: July 10, 2017, 10:58:22 am »
That was one of the big questions. I have compiled a rather long list with scopes which included the Wavepro 900 series (preferably a 960) and even the Wavepro 7000 but in the end I had to be sensible and look at what unique features an older >1GHz scope would really add to my lab and the answer was: bandwidth and a noisy dog house.

Oh yes, these scopes are loud, and quite large.

The small and less noisy alternative would be a WaveRunner2 LT584 (1Ghz) but they are somewhat rare (and often vastly overpriced).

Quote
So I opted for a model which was relatively small, light and cheap. Spending more would mean buying features I already have.

Makes sense. I know you already have other scopes.

Quote
The 54835A is not going to be my daily use scope. I will only switch it on if I need the bandwidth.

I use my DSO8064A as my main scope now, mostly because it's less noisy and a bit smaller than the WavePro 7k. What's annoying though is how expensive active probes are for Infiniium scopes, even 2nd hand.
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Offline snoopy

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #27 on: July 10, 2017, 12:58:11 pm »
Does this help ?

 

Offline Jwalling

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #28 on: July 10, 2017, 02:37:11 pm »
transfer lots of data in a single pass.

writing a shitload of stuff to a usb key will often cause the interface to hang after while.
i imagine any streaming devices like tuners will cause absolute chaos.
btw, the first intel chipsets with usb 1.0 had the bug too - it was in the design spec they where supplied with!!!
oops!  :palm:

I copied the entire contents (about 105MB)of the \ossetup directory folder to a thumb drive, then did a FC/B to compare the files. No errors. I'd say it's good enough for government work, when the most likely use is saving screenshots and such.
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Offline free_electron

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #29 on: July 10, 2017, 02:37:58 pm »
here is the clip you need to press.
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Offline Jwalling

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #30 on: July 10, 2017, 02:45:49 pm »
here is the clip you need to press.

You can't. the CH3/4 attenuator assy. covers those.
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Offline nctnico

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #31 on: July 10, 2017, 02:58:23 pm »
here is the clip you need to press.
You can't. the CH3/4 attenuator assy. covers those.
Indeed but it seems to vary between the models. The attenuators in my one are fully enclosed in (bulky) metal shielding so there is no way I can get to the clips.
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Offline Jwalling

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #32 on: July 10, 2017, 03:01:14 pm »
here is the clip you need to press.
You can't. the CH3/4 attenuator assy. covers those.
Indeed but it seems to vary between the models. The attenuators in my one are fully enclosed in (bulky) metal shielding so there is no way I can get to the clips.

Exactly. The dual attenuators on the 54835A/45A cover them. On the 54825A and lower, they may be accessible since there's 4 separate ones.
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Offline nctnico

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #33 on: July 13, 2017, 09:17:58 pm »
Time for an update. On the PC part I added another 256MB (I bought 3 memory modules so why not) and disabled swap (virtual memory).

More importantly I received the replacement ADC hybrid today. After swapping it the self tests pass and channel 1 works so now I have 4 working channels. Woohoooo! Time to put everything together!

I bought some standard HP feet with tilt stands but I quickly found out the 54835A uses different feet. I tried to find the right feet on Ebay but couldn't so time to pull out the drill press and drill some extra holes to hold the most common HP feet:








The end result (200MHz signal with FM modulation):


What is interesting is that the probe interface board shows a lot of use on channel 1, a little bit on channel 2 and none on channel 3 and 4. Also the attenuator relay count is very low. Around 4000 on channel 1 and around 2000 on the other channels.
« Last Edit: July 13, 2017, 09:28:02 pm by nctnico »
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Offline alm

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #34 on: July 13, 2017, 09:39:26 pm »
Thanks for the update. Great that replacing the hybrid turned out to be a complete fix (which was like 90% likely, but you never know until you try it).
 

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #35 on: July 13, 2017, 10:20:59 pm »
Front panel USB connectivity ?

Could you shoehorn one of those USB drive bay panels in where the the floppy drive is ?
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Offline nctnico

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #36 on: July 13, 2017, 10:30:06 pm »
Front panel USB connectivity ?

Could you shoehorn one of those USB drive bay panels in where the the floppy drive is ?
I thought about that. First of all I have not been able to find USB drive panels which fit into a slimeline 3.5" drive. Secondly and worse: Windows98 starts acting up if I DISconnect the drive. This may have to do with the fact that it isn't a normal floppy drive but a combination between a floppy disk and a 120MB optical drive (pretty amazing how they put all that into such a small space). I think I'll opt for a USB extension cable.

edit: Windows98 starts doing weird things when the LS120 is disconnected
« Last Edit: July 14, 2017, 09:16:30 am by nctnico »
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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #37 on: July 13, 2017, 10:41:19 pm »
Front panel USB connectivity ?

Could you shoehorn one of those USB drive bay panels in where the the floppy drive is ?
I thought about that. First of all I have not been able to find USB drive panels which fit into a slimeline 3.5" drive.
Yep, slimline will probably be hard to find but keep an eye out for something proprietary from HP, Dell or similar PC's.
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Offline nctnico

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #38 on: July 13, 2017, 10:50:47 pm »
Thanks for the update. Great that replacing the hybrid turned out to be a complete fix (which was like 90% likely, but you never know until you try it).
Actually there still is a minor issue with channel 4. It doesn't pass vertical calibration. A quick check didn't reveal an obvious attenuator problems so maybe some gain control setting is at it's maximum.
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Offline alm

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #39 on: July 13, 2017, 11:28:10 pm »
Interesting, given the lack of wear on that channel. But maybe they used a BNC cable or a probe that does not have power/ID pins. Could be that one of the resistors drifted after being overloaded.
 

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #40 on: July 14, 2017, 04:06:37 am »
Secondly and worse: Windows98 starts acting up if I connect the drive. This may have to do with the fact that it isn't a normal floppy drive but a combination between a floppy disk and a 120MB optical drive (pretty amazing how they put all that into such a small space).

All those drivers should be in images you got from my link. Mine doesn't have the super drive but I've been thinking of adding it.

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #41 on: July 14, 2017, 09:16:59 am »
Secondly and worse: Windows98 starts acting up if I connect the drive. This may have to do with the fact that it isn't a normal floppy drive but a combination between a floppy disk and a 120MB optical drive (pretty amazing how they put all that into such a small space).
All those drivers should be in images you got from my link. Mine doesn't have the super drive but I've been thinking of adding it.
I made a typo: Windows98 starts acting up when the drive is not connected.
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Offline Jwalling

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #42 on: July 14, 2017, 09:23:49 am »
Secondly and worse: Windows98 starts acting up if I connect the drive. This may have to do with the fact that it isn't a normal floppy drive but a combination between a floppy disk and a 120MB optical drive (pretty amazing how they put all that into such a small space).
All those drivers should be in images you got from my link. Mine doesn't have the super drive but I've been thinking of adding it.
I made a typo: Windows98 starts acting up when the drive is not connected.

The IDE channel on those FIC motherboards is a bit flakey. It doesn't like some PATA SSD drives I've tried either. Maybe the added loading of the LS-120 compensates the bus a bit. One or more ringing signals maybe?
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Offline Wuerstchenhund

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #43 on: July 14, 2017, 10:40:31 am »
The IDE channel on those FIC motherboards is a bit flakey. It doesn't like some PATA SSD drives I've tried either.

The IDE controller in the buggy VIA chipset's Southbridge only supports (some buggy) UDMA-33 (UDMA-2) while most PATA SSDs require at UDMA-100/133 (UDMA-5/6). Also, if I remember correctly (and that's been a long time), only the primary IDE channel even supports UDMA (I think the secondary channel is PIO only).

Personally, I wouldn't bother with SSDs on this scope. Considering the poor performance of the VIA Apollo chipset and the limitations of the OS (Win98) I guess the best option would be an IDE-to-CF adapter. CF cards that support IDE mode usually support PIO modes which might be safer with this chipset than UDMA. Newer cards (Rev. 3 and newer) also support UDMA-33 and UDMA-66 modes (some Rev 2 cards support UDMA-33 as well). A Rev 3 card should be fast enough for this application.

A practical option would be one of the expansion cards that have a CF slot in the slot cover or a slimline CF reader so the card is accessible from outside. It would also allow to easily change between multiple copies i.e. for experimentation, or having a card for each project which contains only stored settings/screenshots/waveforms for that project. It also makes it easy to copy data to a PC.
« Last Edit: July 14, 2017, 10:43:46 am by Wuerstchenhund »
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Offline nctnico

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #44 on: July 14, 2017, 01:39:43 pm »
The problem with IDE CF cards is that these are typically marked as removable media. Some biosses will not boot from these and some software won't install on a removable drive. I have used exactly the same mSata to PATA adapter in my Tektronix TLA715 because of these problems. Still I agree that the motherboard and CPU are rather poor choices. BTW UDMA is disabled in the VA-503A BIOS by default and probably for a good reason.
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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #46 on: July 14, 2017, 03:13:47 pm »
http://www.ebay.co.uk/itm/351131265761
 8)

The scope uses 2.5" drives, but may be possible to use that if you want to hack in a 4 pin disk drive power cable connector, and use the secondary port. Might be easier to find a 2.5" variant.
http://www.ebay.com/itm/2-5-IDE-2-5-PATA-to-scoket-2-M-2-NGFF-SATA-SSD-adapter-card-with-case/322162290175?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2055119.m1438.l2649

Than one does NOT work with the FIC board, though.
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Offline nctnico

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #47 on: July 14, 2017, 03:48:18 pm »
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #48 on: July 14, 2017, 05:15:43 pm »
i posted that version because it matches the motherboard headers.

if you want 2.5" then here:
http://www.ebay.co.uk/itm/332247062499
 

Offline Wuerstchenhund

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #49 on: July 14, 2017, 08:13:56 pm »
The problem with IDE CF cards is that these are typically marked as removable media. Some biosses will not boot from these and some software won't install on a removable drive.

Only in CF mode. Better cards support True IDE mode which means they behave as a IDE drive (fixed or removable). SanDisk (i.e Extreme), Transcend and Apacer have several cards that support True IDE mode in fixed and removable configuration, but usually only for the industrial variants, not the consumer cards.

Also, many of the cheap Chinese CF-to-IDE adapters don't put the card in True IDE mode, which is if I remember right by grounding a specific pin. Also, they don't connect the UDMA-relevant DMAACK/REQ signal pins. Nothing that can't be fixed with a soldering iron and a bit of wire.

Quote
I have used exactly the same mSata to PATA adapter in my Tektronix TLA715 because of these problems.

Never had an TLA but I've replaced IDE hard drives in a lot of similar systems (486 and up), with the right cards and a good adapter no problem.

Quote
Still I agree that the motherboard and CPU are rather poor choices. BTW UDMA is disabled in the VA-503A BIOS by default and probably for a good reason.

Probably. Which means you'd be using MWDMA which limits the board to 16MB/s (I guess a lot less with that chipset), which puts it easily into territory even an older/slower CF card could handle.
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Offline nctnico

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #50 on: July 14, 2017, 11:23:26 pm »
Today I ran the calibration procedure (again because the calibration data from yesterday somehow got lost). According to the log it seems the attenuator for channel 4 (which used to be on channel 2 which was defective) is a little bit off for the 1x (1.024) and 5x (5.092) settings.
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Offline Jwalling

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #51 on: July 14, 2017, 11:31:12 pm »
Today I ran the calibration procedure (again because the calibration data from yesterday somehow got lost). According to the log it seems the attenuator for channel 4 (which used to be on channel 2 which was defective) is a little bit off for the 1x (1.024) and 5x (5.092) settings.

A long-shot, but what if you config back to 54835A?
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Offline nctnico

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #52 on: July 15, 2017, 08:44:34 am »
I'm more inclined to swap the attenuators but the error is so small I don't think it is worth the effort. BTW this is a picture showing the input path (from the help file I found):


These are the calibration results
Code: [Select]
1)
Hf Attenuators:         Passed                                             
         0.991           4.968          10.002          50.212             

2)
Hf Attenuators:         Passed                                             
         0.996           4.988          10.009          50.148             

3)
Hf Attenuators:         Passed                                             
         0.994           4.985          10.000          50.114             

4)
Hf Attenuators:         Failed                                             
         1.014           5.092          10.000          50.000             
Channel 4 is clearly different but the error is less than 2%. Maybe channel 2 got overloaded which damaged the attenuator and destroyed the ADC hybrid.
« Last Edit: July 15, 2017, 08:51:27 am by nctnico »
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Offline Jwalling

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #53 on: July 15, 2017, 01:15:33 pm »
I have an entire ACQ board (unknown status, missing all the A/D converters and has one attenuator module which is known to be bad) Do you think you could use any parts from it? You could have the attenuator module for the cost of shipping.
Some of those Teledyne relays have resistor(s) inside, maybe the one that was overloaded increased the resistance on one of them?
« Last Edit: July 15, 2017, 01:17:32 pm by Jwalling »
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Offline nctnico

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #54 on: July 15, 2017, 02:21:03 pm »
Tempting but I think I'll leave it like it is for now. Also shipping costs may be getting close to buying a new relay if one of them turns out to be bad. I see no obvious resistive divider structures so I guess the attenuation network is inside the relay.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Online TheSteve

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #55 on: July 15, 2017, 02:34:39 pm »
Yep, those are Teledyne attenuators. Far from cheap if you need replacements.
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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #56 on: July 27, 2017, 10:02:53 pm »
Just bought a 54845a so I can join the repair club.
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Offline nctnico

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #57 on: July 27, 2017, 10:19:28 pm »
Just bought a 54845a so I can join the repair club.
Looking forward to read how it goes! I had a bit of a play with mine last week and it has some nice features.
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Offline Neganur

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #58 on: July 28, 2017, 04:22:14 pm »
This one does:
www.ebay.com/itm/Hot-Tested-mSATA-to-2-5-PATA-IDE-Enclosure-Adapter-Case-With-Screws/201268830337

PS, thanks for this! You linked this already quite a while ago in another thread and I bought one together with a Kingston SSD for my E8357A.
Finally got around to clone the drive this evening and everything works as expected :)
 

Offline Tony_G

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #59 on: July 30, 2017, 10:35:43 am »
Just saw this come up on an auction site and thought it might help, if the price is right of course:

http://www.go-dove.com/en/auction/view?id=12334874

No relationship with the site or seller, except that I bought pieces through the auction site before.

Online TheSteve

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #60 on: August 06, 2017, 12:04:07 am »
My 54845A arrived yesterday, picked it up and cracked it open today.
Many of the cables were disconnected - once I got them reconnected and it looked safe I powered it up. It was advertised as having no display, and that was correct, no video at all on the LCD, just a backlight. I connected an external monitor and it gets to the BIOS screen. At the same time I could hear the harddrive clunking like mad - very much dead. I found another 20 gig HD and connected it up. The scope had the original pouch on top and inside was the original floptical recovery media. I removed the floptical drive cleaned it and reinstalled. The disks are from 1999 but so far are still working. Recovery is in progress.

Updates as they happen.

edit - only had a PS2 keyboard so I made an adapter using an 8 PIN din with pins removed and a PS2 socket. Got to 25% recovery and the floptical drive doesn't sound very healthy but is still going.

edit2 - The sucker has an American Megatrends Atlas PCI-III motherboard, a K6-2-/300 CPU and a whopping 64 megs of ram!

edit3 - recovery succeeded and self tests pass. The HD was making too much noise though so I dug out a couple IDE 2.5 inch flash drives, one of them seems to work fine so I am recovering to it.

Once I determine how much is working I will be pulling the front off to have a look at the LCD.
« Last Edit: August 06, 2017, 01:31:21 am by TheSteve »
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Online TheSteve

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #61 on: August 06, 2017, 04:04:05 am »
Well this is encouraging:

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #62 on: August 06, 2017, 04:15:26 am »
Pulled the entire front off the scope. There was a place to push the autoprobe front panel off but the location doesn't match any pictures posted in this thread or the service manual.
After getting the front off I determined the ribbon cable wasn't even plugged into the LCD panel. There were also many missing screws. I reconnected the LCD and am very pleased to see it come to life.
Now I bought this as a parts unit with no display, no other info was known other then it "appeared complete". Several of the case screws were missing in the picture. It was obviously taken apart for some reason and it looks like someone shoved it back together in hurry being so much was disconnected internally.

So far many screws and one of the BNC locking nuts is also missing from the front. I did notice some of the vertical encoders do miss/jump steps - maybe that was the original fault someone was planning to work on and not the LCD panel itself? They are all covered in heavy dust and likely need a good cleaning.

I do see a little pulsing/flicker on the LCD panel as it is warming up - maybe it will get worse, or there is a power supply issue.
VE7FM
 

Online tautech

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #63 on: August 06, 2017, 04:33:10 am »
I do see a little pulsing/flicker on the LCD panel as it is warming up - maybe it will get worse, or there is a power supply issue.
On the screen info or the backlight ?
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Offline Tony_G

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #64 on: August 06, 2017, 05:19:09 am »
Nice, glad to hear it seems to basically work.

As an aside, I've wondered how HP expected you to clip the probe ground to gnd socket for compensation. Seems really easy for it to pop off.

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #65 on: August 06, 2017, 06:54:01 am »
Well no flicker recently, may have been a bad connection to one of the backlite tubes. I have reassembled the unit for now and given it a quick cleaning. There is one screw barely holding the front controls in. I will have to order some longer screws.
Most of the encoders are behaving now but one or two need further cleaning. I tried out a 1152A 2.5 GHz active probe and it calibrates fine on each channel. I will have to find a way to upgrade the software - this MB has no USB. And I don't have any spare magneto optical media floating around. It was nice to find the original Win98 license and restore media in the top pouch - that has gotta be quite uncommon.

I am trying out 8 GS/s mode, here is a 1.5 GHz 1 Vpp signal. If I go higher in frequency the attenuation isn't too bad but before 1.6 GHz triggering stops.

edit - took a while but I finally found the proper length M3x0.5 26mm screws in my collection (20 year old radio control parts). Also found some screws to use on the case so the scope is no longer missing any screws. The rotary encoders were also cleaned a second time and seem pretty good now.
« Last Edit: August 06, 2017, 10:45:14 pm by TheSteve »
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Offline nctnico

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #66 on: August 06, 2017, 07:36:36 am »
Dang! I wish I bought that one! I guess the previous owner didn't had any knowledge about PCs and started pulling cables.
Does it also pass it's self calibration?
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Online TheSteve

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #67 on: August 06, 2017, 07:41:48 am »
Dang! I wish I bought that one! I guess the previous owner didn't had any knowledge about PCs and started pulling cables.
Does it also pass it's self calibration?

Yes, self test and self calibration both pass. So far I am very impressed, I have less then $290 USD into it including the shipping.
Guess I can't complain too much that it only had 3 feet. For the moment it has the two front feet installed.

Amazing how much hardware is in it compared to my MSOX3000T series scope...
« Last Edit: August 06, 2017, 07:43:53 am by TheSteve »
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Offline nctnico

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #68 on: August 06, 2017, 04:09:13 pm »
Dang! I wish I bought that one! I guess the previous owner didn't had any knowledge about PCs and started pulling cables.
Does it also pass it's self calibration?
Yes, self test and self calibration both pass. So far I am very impressed, I have less then $290 USD into it including the shipping.
Oh, yes please RUB IT IN!  ;)
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #69 on: August 06, 2017, 07:03:05 pm »
Here are a couple shots showing SWR (return loss) of the input. I don't know if this would change at all if the scope was rejumpered to a 54846A etc. It is interested to note it uses 4 different ranges, the MSOX3000 series uses only two.

20mV/div
50mV/div
200mV/div
500mV/div



VE7FM
 

Online TheSteve

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #70 on: August 07, 2017, 10:56:19 pm »
Decided I should try upgrading from version 3.50 today.
As nctnico has already mentioned the built in upgrade tool only wants to read from the Magneto Optical drive. He used a hex editor to change the path so he could read the upgrade files from a USB drive. My scope has no USB ports so I tried something else.
I unpacked the 4_3_upg upgrade package on my desktop and copied the files directly to the scopes hard drive. I then booted the scope, killed the scope app and used explorer to copy the files to c:\scope\upgrade\scope\temp\
Once the files are copied you can run HP548UPG.exe directly from that directory and it will perform the upgrade.
With version 4.3 running I removed all of the files from the upgrade directory and repeated the process with the 4.5 update.
It was a pretty hassle free way to upgrade the scope. Going from version 3.5 to 4.3 easily doubles the boot time of the scope(3.5 direct to 4.5 might not as it will skip the web features). I suppose that is the tradeoff for adding the built in webserver with webcontrol. If nothing else it makes it easy to grab screen shots.

VE7FM
 
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Offline Jwalling

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Offline nctnico

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #72 on: August 12, 2017, 10:18:03 am »
This just showed up if you're interested nctnico.
http://www.ebay.com/itm/Agilent-HP-Keysight-54845-66502-Attenuator-for-54845A-54845B-54835A-T7-B17-/182713390428?epid=12003971610&hash=item2a8a91155c:g:a3AAAOSw8VJZjg9C
Interesting but I think a new relay may be cheaper and there is also the question whether the relays aren't worn on an attenuator from Ebay.
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Offline eurofox

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #73 on: August 17, 2017, 04:43:59 pm »
I joint the club, just won a dead 54845A, nice cosmetic with install disk, manuals, original keyboard and mouse.
eurofox
 

Offline Tony_G

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #74 on: August 17, 2017, 07:07:47 pm »
I joint the club, just won a dead 54845A, nice cosmetic with install disk, manuals, original keyboard and mouse.

Nice - Look forward to seeing the photos and the story of bringing it back to life.

Offline JanNousiainen

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #75 on: August 22, 2017, 02:07:09 pm »
Yay, I will join the club too :)

Just got a broken 54845A from my employer for free. It was working well and was even calibrated recently but then all channels started to show signal being over the vertical range and there was three FAIL's on self test and on that point the scope program just crashed. Original mouse, keyboard and mouse mat follows the scope.

Symptoms sounds pretty similar as in here:

http://www.dasarodesigns.com/projects/fixing-an-hp-agilent-54845a-infinium-oscilloscope/

With a bit of luck this could actually be fixed and then I have pretty impressive scope compared to what I have now :)
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Offline Tony_G

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #76 on: August 22, 2017, 05:19:05 pm »
Yay, I will join the club too :)

Just got a broken 54845A from my employer for free.

Good luck with it - If you need it I have the software hosted further up in the thread I think. If you can't find the link let me know and I'll repost.

TonyG

Offline JanNousiainen

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #77 on: August 23, 2017, 07:58:31 am »
Had time to snap few photos:

20935000_10155501727973463_374710227212071001_o by Jan Nousiainen, on Flickr

21014096_10155501726808463_3357537562277012915_o by Jan Nousiainen, on Flickr

21014043_10155501734243463_7132642189203810817_o by Jan Nousiainen, on Flickr

20988433_10155501729338463_4532608220713741416_o by Jan Nousiainen, on Flickr

K6-200 CPU, 16 MB of RAM, 1,3 GB HDD and Windows 95... You cannot get lower specs even if you tried I think :P

Most obvious things to upgrade, RAM and CPU? Will this unit run Windows 98 straight away?
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Offline zucca

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #78 on: August 23, 2017, 08:30:54 am »
JanNousiainen never turn it on, without taking it apart first.  :-/O

Looks like you have some adventure in front of you with that scope, please keep us posted.
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Offline nctnico

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #79 on: August 23, 2017, 08:38:56 am »
I'd fix/diagnose the problems first and then start thinking about upgrading.
I think you have an older model so you have to investigate what kind of processor and memory the motherboard will work with.
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Offline Tony_G

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #80 on: August 23, 2017, 02:53:31 pm »
Just adding this here in case it's useful to you:

you can launch scope.exe using the service command  " scope.exe /service" that gives extra options in the self test menu where you can set attenuator click and othe roptions

Also you should be able to use the link to the scope software to upgrade to Win98 - I'm not sure what the experience will be like but I'd check the PDF that describes the process and limitations first.

TonyG

Offline eurofox

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #81 on: August 23, 2017, 08:38:15 pm »
My scope on the way to my home, should be here in about 2 weeks.



eurofox
 

Offline JanNousiainen

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #82 on: August 24, 2017, 09:45:03 am »
Ran the scope app with /service option and got boatload of new fails, too many to mention. Opened the case to have a quick look inside but saw nothing obvious.

Well, atleast the external display works :)

IMG_20170823_220033 by Jan Nousiainen, on Flickr

Info screen:

IMG_20170823_220134 by Jan Nousiainen, on Flickr

AMI Atlas III motherboard, propably oldest used in Infiniums?

IMG_20170823_225438 by Jan Nousiainen, on Flickr

Trying to make room on my desk to start proper inspection, supply voltages and bypassing attenuators by feeding signal straight to hybrids etc.

What needs to be removed to get the attenuator modules out?
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Offline JanNousiainen

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #83 on: August 30, 2017, 12:35:31 pm »
Still cleaning desk (and installing more sockets to lab etc) to be able to start proper debugging  >:(

Being overly optimistic, ordered some 64 MB of RAM in addition of current 16 MB to allow Windows 98 to run which is required to run later SW. Where can I find the update images/files? I think I need IDE CD-ROM too?
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Offline Tony_G

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #84 on: August 30, 2017, 03:19:49 pm »
In case you need it I saved a copy of the software folders from the Keysight FTP Server (they went missing last time I checked there)

https://1drv.ms/f/s!Amqar8_XQ9Uzj6YhN1xHdM8tQdKMOA

TonyG

I used a parallel port CD-ROM drive I bought from eBay ("MicroSolutions Backpack Parallel Port CD-ROM Drive", I paid $14 for it but I took a quick look and they seem to be much more expensive now). Apparently you can hook up an IDE CD ROM drive on the secondary IDE channel though so I'd try that path, especially if you have one laying around already.

TonyG

Offline JanNousiainen

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #85 on: August 30, 2017, 10:52:13 pm »
Holy freaking crap!  :o

I followed through this article and did some measurements: http://www.dasarodesigns.com/projects/fixing-an-hp-agilent-54845a-infinium-oscilloscope/

And guess what? In my scope the -3.1V supply shows +0.8V, same as in his scope! So it is probably failed opamp in my scope too!  Could it really be so simple? ^-^

Going to order few LT2726 IC's ASAP...
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Offline JanNousiainen

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #86 on: August 31, 2017, 06:36:30 am »
In case you need it I saved a copy of the software folders from the Keysight FTP Server (they went missing last time I checked there)

https://1drv.ms/f/s!Amqar8_XQ9Uzj6YhN1xHdM8tQdKMOA

TonyG

I used a parallel port CD-ROM drive I bought from eBay ("MicroSolutions Backpack Parallel Port CD-ROM Drive", I paid $14 for it but I took a quick look and they seem to be much more expensive now). Apparently you can hook up an IDE CD ROM drive on the secondary IDE channel though so I'd try that path, especially if you have one laying around already.

TonyG

Thank you for the link :) I think I will try the IDE CD-ROM first, could be easier and faster to source one of those. Or, I do have few already but they are in different country than me...
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Offline JanNousiainen

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #87 on: August 31, 2017, 06:48:05 am »
Now a stupid Infinium noob question  :P

Do the upgrades only contain the scope SW and not OS? Looking at the upgrade file sizes that might be the case? I have not yet upgraded SW so I don't know.

If updates only contain scope SW and it is OS independent, can I just install Windows XP to my scope (now Windows 95) and then install upgrade on that? Provided that my ancient HW is able to run XP that is.
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Online TheSteve

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #88 on: August 31, 2017, 07:33:15 am »
The upgrades I have used are scope applications only. Based on what I've read I'd stick with Win98.
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Offline nctnico

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #89 on: August 31, 2017, 09:49:04 am »
I tried to install XP but the problem is that the drivers for the acquisition card are not available. The Windows98 drivers won't work on XP because XP is completely different when it comes to drivers.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline zucca

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #90 on: August 31, 2017, 12:42:06 pm »
same old story, only bad SW can stop good HW EE
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Offline Howardlong

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #91 on: August 31, 2017, 01:50:49 pm »
I tried to install XP but the problem is that the drivers for the acquisition card are not available. The Windows98 drivers won't work on XP because XP is completely different when it comes to drivers.

Do you know what the VIDs/PIDs are for the acq card? Maybe in the range 15BC:0500 to 15BC:0507?
 

Offline Tony_G

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #92 on: August 31, 2017, 03:58:48 pm »
The full software should be in there - Drill into the 54845A folder and you'll see a bunch of folders marked XX_recovery - Those should have the full OS versions in them - I'm not sure how it works out what the OS to install is but the file sizes are right for that.

My Scope was Win98 and I started from the 3_5_recovery image and then did the 4_x updates.

TonyG

Offline eurofox

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #93 on: August 31, 2017, 04:09:47 pm »
I should get mine tomorrow, I will post my repair progress here if ntcnico don’t mind that we pollute he’s post but I think it is a good idea to keep the repair of the same instrument in one post.  :horse:
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Offline nctnico

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #94 on: August 31, 2017, 06:45:09 pm »
No objections from me. It's Dave's forum anyway  :P
Looking forward to what you find!
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline JanNousiainen

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #95 on: August 31, 2017, 09:48:13 pm »
Holy freaking crap!  :o

I followed through this article and did some measurements: http://www.dasarodesigns.com/projects/fixing-an-hp-agilent-54845a-infinium-oscilloscope/

And guess what? In my scope the -3.1V supply shows +0.8V, same as in his scope! So it is probably failed opamp in my scope too!  Could it really be so simple? ^-^

Going to order few LT2726 IC's ASAP...

Hmmmmm, also +0.85V regulator output looks funny, Vout is 3.9V. Perhaps good idea to replace that one too, type is LT1086CM. Not sure what the ADJ pin should be at, mine is about +2.5V.
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Offline eurofox

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #96 on: September 05, 2017, 01:09:32 pm »
I got finally my scope today.  :-+

Very big surprise when power up, start …. Boot ….. no error …. Pass al tests.  :-DD :-+ :-+ :popcorn:

It was sold “as is” with no warranty, was sold by someone who know nothing about instruments and buy from closing business ….  :horse:

I got one brand new probe with it. Got the original installations disks still sealed.   :bullshit:

After cleaning up it is in a near mint condition, only minor problem I have to replace the legs but this is not a problem.  :wtf:


« Last Edit: September 05, 2017, 01:11:30 pm by eurofox »
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Offline nctnico

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #97 on: September 05, 2017, 02:12:06 pm »
@eurofox:  Great find :-+ sometimes people can get lucky!
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline Tony_G

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #98 on: September 05, 2017, 02:39:00 pm »
I've always wondered how HPAK expected the probe ground to connect to the grounding plug given that they have alligator clips on the probes and a socket for the ground....

Anyway, glad to see you scored there - Hopefully Jan does the OpAmp swap and it starts working too.

TonyG

Offline Jwalling

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #99 on: September 05, 2017, 03:35:02 pm »
I got finally my scope today.  :-+

Very big surprise when power up, start …. Boot ….. no error …. Pass al tests.  :-DD :-+ :-+ :popcorn:

Does it pass the calibration as well?
Jay

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Online TheSteve

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #100 on: September 05, 2017, 04:23:53 pm »
I've always wondered how HPAK expected the probe ground to connect to the grounding plug given that they have alligator clips on the probes and a socket for the ground....

Anyway, glad to see you scored there - Hopefully Jan does the OpAmp swap and it starts working too.

TonyG

The probe ground is actually very easy to clip too. It isn't a regular banana socket.
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Offline Jwalling

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #101 on: September 05, 2017, 04:38:30 pm »
I've always wondered how HPAK expected the probe ground to connect to the grounding plug given that they have alligator clips on the probes and a socket for the ground....

Anyway, glad to see you scored there - Hopefully Jan does the OpAmp swap and it starts working too.

TonyG

The probe ground is actually very easy to clip too. It isn't a regular banana socket.

And you can always clip it to the AUX out BNC shell anyway...
Jay

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Offline Howardlong

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #102 on: September 05, 2017, 05:23:19 pm »
A quick glance of the service manual suggests that the attenuators are a different part number for the 54846a. Are there any thoughts on the hackability up to this version? There was some mention of an extra resistor, R4, somewhere on the acquisition board, but I fear there may be more to it.
 

Offline eurofox

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #103 on: September 05, 2017, 06:16:10 pm »
I got finally my scope today.  :-+

Very big surprise when power up, start …. Boot ….. no error …. Pass al tests.  :-DD :-+ :-+ :popcorn:

Does it pass the calibration as well?

Yep, just finish it.  :popcorn:

eurofox
 

Offline Tony_G

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #104 on: September 05, 2017, 07:38:17 pm »
The probe ground is actually very easy to clip too. It isn't a regular banana socket.

Hmm, my clips always seem to slip off at the slightest movement. I'll have to take a close look at the socket.

TonyG

Offline eurofox

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #105 on: September 06, 2017, 04:56:25 am »
And now the 2 cent question  :wtf:

How can options be enabled on infinium scopes?  :palm:

If I look to what this guy did, he enabled all available options. :clap:

All Enabled Options.
64MPts, EZJIT Plus, High Speed Serial, Low Speed Serial, Force 1G, User Def Fn, eGUI, Voice, Power, PRMLpro, PRMLpro 2, PMRLpro 3, PRMLpro 4, PRMLpro 5, App Remote, Gigabit Ethernet, DVI, HDMI, USB, Wireless USB, USB3 Compliance, Xilinx Probe, Altera Probe, Fibre Channel, CAN, FB DIMM, Express Card, SATA 1, SATA 2, SATA 6 Upgrade, SAS, DDR1, DDR2, DDR3, GDDR, GDDR3, GDDR4, GDDR5, MIPI, Display Port, FlexRay, My Compliance, AP3, AP4, AP5. Some options are officially not supported for this scope model.

http://www.ebay.pl/itm/Agilent-54831D-MSO-4an-16dig-wUpgraded-Motherboard-cpu-2-3-2GHz-RAM-SSD-ALL-OPTS/291821246325
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Offline Howardlong

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #106 on: September 06, 2017, 05:51:48 am »
And now the 2 cent question  :wtf:

How can options be enabled on infinium scopes?  :palm:

If I look to what this guy did, he enabled all available options. :clap:

All Enabled Options.
64MPts, EZJIT Plus, High Speed Serial, Low Speed Serial, Force 1G, User Def Fn, eGUI, Voice, Power, PRMLpro, PRMLpro 2, PMRLpro 3, PRMLpro 4, PRMLpro 5, App Remote, Gigabit Ethernet, DVI, HDMI, USB, Wireless USB, USB3 Compliance, Xilinx Probe, Altera Probe, Fibre Channel, CAN, FB DIMM, Express Card, SATA 1, SATA 2, SATA 6 Upgrade, SAS, DDR1, DDR2, DDR3, GDDR, GDDR3, GDDR4, GDDR5, MIPI, Display Port, FlexRay, My Compliance, AP3, AP4, AP5. Some options are officially not supported for this scope model.

http://www.ebay.pl/itm/Agilent-54831D-MSO-4an-16dig-wUpgraded-Motherboard-cpu-2-3-2GHz-RAM-SSD-ALL-OPTS/291821246325

A lot of those options don't work with the 54831D.

https://www.eevblog.com/forum/testgear/agilent-54831d-modernising/msg1144527/#msg1144527 and you add the optioms you want to the licence file. Of course that hack only works with 5.71 software, I am not sure that version works with the 54835/45/46?
 

Offline JanNousiainen

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #107 on: September 06, 2017, 10:37:50 am »
Got 64 MB of RAM yesterday, installed and seemed to work. Today I should have the replacement op amps in my hands. Also ordered regulator for 0.85V rail. Looking for 2.5" IDE HDD to install Win 98 (do not feel like installing on original HDD) and newer software. Also IDE CD-ROM drive is needed.

Is there RS232/SPI/I2C serial decode option for early Infiniums? Or any other options apart from USB testing voice control? All the literature I have seen has been pretty thin on that respect.
« Last Edit: September 06, 2017, 10:40:52 am by JanNousiainen »
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Offline eurofox

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #108 on: September 06, 2017, 10:54:32 am »
Got 64 MB of RAM yesterday, installed and seemed to work. Today I should have the replacement op amps in my hands. Also ordered regulator for 0.85V rail. Looking for 2.5" IDE HDD to install Win 98 (do not feel like installing on original HDD) and newer software. Also IDE CD-ROM drive is needed.

Is there RS232/SPI/I2C serial decode option for early Infiniums? Or any other options apart from USB testing voice control? All the literature I have seen has been pretty thin on that respect.

I'm not sure that the extra RAM will speed up the oscilloscope software, it seems that limited OS resources are used by the oscilloscope software, on my scope it is very responsive.

I hope that the new IC will solve your problem.

I think power analysis software was available as well but you are right, there is limited information available about the options.

« Last Edit: September 08, 2017, 08:23:11 pm by eurofox »
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Offline JanNousiainen

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #109 on: September 06, 2017, 11:04:52 am »
I'm not sure that the extra RAM will speed up the oscilloscope software, it seems that limited OS resources are used by the oscilloscope software, on my scope it is very responsive.

I hope that the new IC will solve your problem.

I had only 16 MB to start with, that is enough for Windows 95 my unit has but not enough for Windows 98 that is required by last applicable scope SW I believe. So I had to get bit more. There is VRM (voltage regulation module) on motherboard, if I could find a way to drop it's output voltage  from 2.9 V to around 2.2 V I could fit much faster processor. Not that it would make much difference to scope performance I guess :)

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Offline nctnico

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #110 on: September 06, 2017, 11:13:41 am »
I did measure an increase in waveforms/s with a faster processor. If you install a lot of memory (which costs peanuts anyway) you can disable swap which will also make Windows work faster.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline eurofox

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #111 on: September 06, 2017, 01:10:30 pm »
I'm not sure that the extra RAM will speed up the oscilloscope software, it seems that limited OS resources are used by the oscilloscope software, on my scope it is very responsive.

I hope that the new IC will solve your problem.

 I could find a way to drop it's output voltage  from 2.9 V to around 2.2 V I could fit much faster processor. Not that it would make much difference to scope performance I guess :)


A diode will do the job  :)
eurofox
 

Offline nctnico

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #112 on: September 06, 2017, 02:26:38 pm »
A diode won't work because it's forward voltage depends a lot on the current. Even a Schottky diode will drop close to 1V at higher currents.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline markb82

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #113 on: September 07, 2017, 09:01:12 am »
A diode won't work because it's forward voltage depends a lot on the current. Even a Schottky diode will drop close to 1V at higher currents.

How about an NPN diode connected (collector to base), which should give you 0.6V even at high currents (within reason).
 

Offline JanNousiainen

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #114 on: September 07, 2017, 09:15:31 pm »
OMG  :o

IMG_20170907_222730 by Jan Nousiainen, on Flickr

IMG_20170907_222745 by Jan Nousiainen, on Flickr

IMG_20170907_225718 by Jan Nousiainen, on Flickr

It fukken works! I got 1.5 GHz 8 GS/s scope for price of 4€ opamp  8) Now I can justify spending bit money to get second IDE HDD and CD-ROM for upgrade to Windows 98.
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Offline nctnico

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #115 on: September 07, 2017, 09:28:44 pm »
Can somebody lock this thread?  :rant: Everyone seems to get these scopes cheaper and with far less serious problems than mine  :-BROKE I cannot stand it!  ;)
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 
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Online TheSteve

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #116 on: September 07, 2017, 10:15:31 pm »
Does calibration pass?
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Offline eurofox

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #117 on: September 07, 2017, 10:37:35 pm »
Really glad that you could fix it  :-+
And now a calibration run  :clap:
eurofox
 

Offline Tony_G

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #118 on: September 07, 2017, 11:58:40 pm »
Nice - It seems that this is the month for these things to become available - There were a few on the auction sites I frequent.

TonyG

Offline eurofox

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #119 on: September 08, 2017, 12:41:57 pm »
Question about updating the software:

The actual version is 3.7

I manage to move 3.73 (10 floppy disk), 4.3 (3 files) and 4.5 (3 files) by using the network to drive C: in a directory “update”.

Since I don’t want to brick my scope and in all documentation only floppy or CDROM options are discussed.
From the utility menu the upgrade function only work with the floppy, trying to run the exe file (with windows Explorer) start the scope software existing software …. Strange. |O

Is it really needed to use a CDROM to update the software?  :palm:

It all depend of the installation procedure build in the exe update file. :horse:
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Offline nctnico

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #120 on: September 08, 2017, 01:19:34 pm »
A few posts back someone described how to upgrade without disk/CDROM. You need to unpack the files to a specific directory and restart the oscilloscope.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline eurofox

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #121 on: September 08, 2017, 02:58:28 pm »
A few posts back someone described how to upgrade without disk/CDROM. You need to unpack the files to a specific directory and restart the oscilloscope.

Thank you for drawing my attention to this post, I missed this one.  :palm:

I did something similar from another directory and it was not working.  :--

By following the procedure it worked like a charm, the directory “update” was hidden.  :wtf:

After the 4.3 USB analyse was enabled and disappear after installation of 4.5.  :-DD
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Offline eurofox

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #122 on: September 08, 2017, 09:15:46 pm »

Is there RS232/SPI/I2C serial decode option for early Infiniums? Or any other options apart from USB testing voice control? All the literature I have seen has been pretty thin on that respect.

Here is the list  :-+

http://www.keysight.com/en/pd-1143488-pn-N5445A/infiniium-application-server-license-for-infiniium-oscilloscopes?pm=OP&nid=-32976.685330&cc=GB&lc=eng
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Offline Jwalling

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #123 on: September 08, 2017, 09:26:23 pm »

Is there RS232/SPI/I2C serial decode option for early Infiniums? Or any other options apart from USB testing voice control? All the literature I have seen has been pretty thin on that respect.

Here is the list  :-+

http://www.keysight.com/en/pd-1143488-pn-N5445A/infiniium-application-server-license-for-infiniium-oscilloscopes?pm=OP&nid=-32976.685330&cc=GB&lc=eng

Pretty sure none of those work on the first generation Infiniiums.
"User must have Infiniium firmware revision A.05.30 or later"

That version number FW is for the 54830B/D series or later.

EDIT: In fact, other than voice control, the only SW options I know of are are runt triggering (standard on the 54835A and 54845A) and communication masks.

Has anybody ever played with voice control? I've never seen that in action...
« Last Edit: September 08, 2017, 09:32:21 pm by Jwalling »
Jay

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Offline eurofox

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #124 on: September 09, 2017, 09:33:21 am »
My scope is now 100% OK and update to the latest version.  :-+

Now the probe problem, I have 1 new 1161A supplied with the scope, maybe I’ll try to get another one on a “decent” price but need to come from Europe since shipping and duty make it not affordable in comparison to the investment of the scope.  |O

I will maybe buy 2 or 4 200mhz probes from Hantek, they are not expensive.  ???

Now why having a 1.5ghz scope and not having the appropriate probes?  :phew:

They are too expensive, 500-800€ and more + shipping cost + duty’s for 1 probe!  |O

Why not build one like this one : https://elektrotanya.com/files/forum/2009/10/e04a036.pdf  :-BROKE

But put it in an aluminium tube or buy one like this one : http://www.benl.ebay.be/itm/RF-Active-Probe-0-1-1500-MHz-1-5-GHz-analyzer-oscilloscope/332253695460?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2055119.m1438.l2649

It should be possible to get power from the autoprobe, I could manage to build a BNC connector with a pin to get the right voltage needed for this kind of probe.  :bullshit:

Anybody experience in this area?
eurofox
 

Offline lukier

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #125 on: September 09, 2017, 10:19:01 am »
Why not build one like this one : https://elektrotanya.com/files/forum/2009/10/e04a036.pdf  :-BROKE

But put it in an aluminium tube or buy one like this one : http://www.benl.ebay.be/itm/RF-Active-Probe-0-1-1500-MHz-1-5-GHz-analyzer-oscilloscope/332253695460?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2055119.m1438.l2649

I remember reading threads here about these probes, even wanted to DIY something, but then I scored multiple (single/diff) LeCroy active probes for a decent price. What stuck to me is that all these DIY designs are "RF" probes and AC coupled (no DC) and I wondered if this could be a problem.
 

Offline Howardlong

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #126 on: September 09, 2017, 03:21:10 pm »
My scope is now 100% OK and update to the latest version.  :-+

Now the probe problem, I have 1 new 1161A supplied with the scope, maybe I’ll try to get another one on a “decent” price but need to come from Europe since shipping and duty make it not affordable in comparison to the investment of the scope.  |O

I will maybe buy 2 or 4 200mhz probes from Hantek, they are not expensive.  ???

Now why having a 1.5ghz scope and not having the appropriate probes?  :phew:

They are too expensive, 500-800€ and more + shipping cost + duty’s for 1 probe!  |O

Why not build one like this one : https://elektrotanya.com/files/forum/2009/10/e04a036.pdf  :-BROKE

But put it in an aluminium tube or buy one like this one : http://www.benl.ebay.be/itm/RF-Active-Probe-0-1-1500-MHz-1-5-GHz-analyzer-oscilloscope/332253695460?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2055119.m1438.l2649

It should be possible to get power from the autoprobe, I could manage to build a BNC connector with a pin to get the right voltage needed for this kind of probe.  :bullshit:

Anybody experience in this area?

The 1152A 2.5GHz 100k ohm 0.6pF FET probe is frequently available for a reasonable price, but just make sure it comes with a good set of the accessory parts, particularly the walking stick ground seems to go amiss. You can survive without it by jury rigging your solution but it's not best solution.

Also the 54006a 10:1 & 20:1 (500 and 1k ohm) 0.25pF 6GHz resistive passive probe, again make sure it comes with accessories including the walking stick probe assemblies, spare resistors, AC coupler, SMA cable and the SMA-BNC adapter.

Plus...
N2874A 10:1 1.5GHz resistive (500 ohm) 2pF passive probe.
N2876A 100:1 1.5GHz resistive (5k ohm) 2.5pF passive probe.
 

Offline nctnico

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #127 on: September 10, 2017, 11:24:56 am »
I tried to install XP but the problem is that the drivers for the acquisition card are not available. The Windows98 drivers won't work on XP because XP is completely different when it comes to drivers.
Do you know what the VIDs/PIDs are for the acq card? Maybe in the range 15BC:0500 to 15BC:0507?
No, according to the list from the BIOS I think it is 103C:1020 (that is the only unknown PCI device listed)
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline JanNousiainen

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #128 on: September 10, 2017, 04:31:50 pm »
Welp, mine is out of commission again :o I tried to update SW from HDD but setup quit before end because I had IE3, not IE4... Now scope loader just freezes.

I guess I will be getting few IDE HDD's and CD-ROM and start from scratch.

Managed to get Win 95 and Win 7 machines to see eachother in network but could not log in to shares from either one. So I set up a http server in Win7 and downloaded update SW to scope that way.
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Offline Neganur

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #129 on: September 10, 2017, 05:59:18 pm »
You should be able to just hook the HDD to your win7 machine and access the files directly.
 

Offline JanNousiainen

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #130 on: September 11, 2017, 07:22:35 am »
You should be able to just hook the HDD to your win7 machine and access the files directly.

None of the machines I have at hand have IDE bus, only SATA. I do have older machines with IDE but they are about 1000 km away...

USB to IDE adapter would work. I have one of those but you guessed it, it is also somewhere else. I'll check if I can get cheap one locally.
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Offline eurofox

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #131 on: September 11, 2017, 07:59:40 am »
You should be able to just hook the HDD to your win7 machine and access the files directly.

None of the machines I have at hand have IDE bus, only SATA. I do have older machines with IDE but they are about 1000 km away...

USB to IDE adapter would work. I have one of those but you guessed it, it is also somewhere else. I'll check if I can get cheap one locally.

I have since several years a device that connect USB to all common hard disk technology, ATA, SATA, IDE ….
I don’t remember the price I pay for it but it was quite cheap.



I’m surprised that you got problems to transfer the updates over the network.
I reinstall de driver for network card, enable Microsoft client with TCPIP and allow disk sharing without password.
On my Windows 10 notebook I make “discovery of network” active, the scope was discovered and provide access to the hard disk of the scope and this ways I could transfer the update files.

« Last Edit: September 11, 2017, 08:13:20 am by eurofox »
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Offline eurofox

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #132 on: September 11, 2017, 10:10:55 am »
My scope is now 100% OK and update to the latest version.  :-+

Now the probe problem, I have 1 new 1161A supplied with the scope, maybe I’ll try to get another one on a “decent” price but need to come from Europe since shipping and duty make it not affordable in comparison to the investment of the scope.  |O

I will maybe buy 2 or 4 200mhz probes from Hantek, they are not expensive.  ???

Now why having a 1.5ghz scope and not having the appropriate probes?  :phew:

They are too expensive, 500-800€ and more + shipping cost + duty’s for 1 probe!  |O

Why not build one like this one : https://elektrotanya.com/files/forum/2009/10/e04a036.pdf  :-BROKE

But put it in an aluminium tube or buy one like this one : http://www.benl.ebay.be/itm/RF-Active-Probe-0-1-1500-MHz-1-5-GHz-analyzer-oscilloscope/332253695460?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2055119.m1438.l2649

It should be possible to get power from the autoprobe, I could manage to build a BNC connector with a pin to get the right voltage needed for this kind of probe.  :bullshit:

Anybody experience in this area?

The 1152A 2.5GHz 100k ohm 0.6pF FET probe is frequently available for a reasonable price, but just make sure it comes with a good set of the accessory parts, particularly the walking stick ground seems to go amiss. You can survive without it by jury rigging your solution but it's not best solution.

Also the 54006a 10:1 & 20:1 (500 and 1k ohm) 0.25pF 6GHz resistive passive probe, again make sure it comes with accessories including the walking stick probe assemblies, spare resistors, AC coupler, SMA cable and the SMA-BNC adapter.

Plus...
N2874A 10:1 1.5GHz resistive (500 ohm) 2pF passive probe.
N2876A 100:1 1.5GHz resistive (5k ohm) 2.5pF passive probe.

The 1152A with accessories go for more than what I pay for the not working scope.

On the top of that they are usually available on the US market, this mean a lot of shipping cost and import duties.

This is the classical problem when you buy a second and high bandwidth scope, the probes cost are equal or superior of the scope itself because on the second hand market, a working probe is sold from 25% to 50% of the a new one, the scope is from 5% (not working) to 25% for a working one.
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Offline JanNousiainen

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #133 on: September 11, 2017, 08:42:55 pm »
Bought USB -> IDE / SATA adapter with power supply for drive and 2 x 40 GB IDE HDD for 25€, now I have to wait for them to arrive from china...
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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #134 on: September 11, 2017, 11:04:59 pm »
The 1152A with accessories go for more than what I pay for the not working scope.

On the top of that they are usually available on the US market, this mean a lot of shipping cost and import duties.

This is the classical problem when you buy a second and high bandwidth scope, the probes cost are equal or superior of the scope itself because on the second hand market, a working probe is sold from 25% to 50% of the a new one, the scope is from 5% (not working) to 25% for a working one.
Even for a new scope its normal to spend equal to or more than the purchase price on probes. If you're stuck with your mindset of cheap broken scopes for repairs then you should buy broken probes and repair them to go with it.
 

Offline eurofox

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #135 on: September 14, 2017, 03:15:07 pm »
I wake up this thread with respect to USB on the scope.

According the experience of ntcnico, it seems that removing the floppy create some problem, it is a pity because usb floppy slim emulator are available and they are cheap.  :wtf:

Other solution since I think there is one PCI slot free on the motherboard is installing a PCI USB adapter with support for Win98, they are available on ebay second hand for a few €.

I just checked the rise time from my Infiniium scope, 232ps, this confirm the 1.5GHz bandwidth.  :-+
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Offline eurofox

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #136 on: September 22, 2017, 02:09:25 pm »
Update on my scope:
USB: My motherboard support 2 USB connections on the motherboard.

I bought this unit: http://electromyne.de/Server-Parts-Supermicro-FPUSB813-Server-Front-Panel-2x-USB-Serial-COM-RS232-Silver-Silber.html
Fit perfectly in the place of the original floppy, com port as well on the front.
It is plug & play and no need to pray, cables, screws all fit perfectly, com2 is now connected to the front panel.  :-DD

Manage in the bios to disable the floppy and work without problem with the floppy removed.  :clap:

I added as well memory, very cheap from the same shop and was shipped in 2 days door to door from Germany.  :-+

Got the exact colour to repair the little scratches and blemish, now my scope is in a real mint condition.

Install a pdf printer emulator.  :popcorn:

Now hunting for probes.  |O


« Last Edit: September 22, 2017, 02:12:00 pm by eurofox »
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Offline Tony_G

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #137 on: September 22, 2017, 02:58:45 pm »
I added as well memory, very cheap from the same shop and was shipped in 2 days door to door from Germany.  :-+

What was the real impact of adding the memory? Was it just faster operation due to less swap file access or did it make the actual scope memory depth better?

TonyG

Offline Jwalling

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #138 on: September 22, 2017, 03:01:04 pm »
I bought this unit: http://electromyne.de/Server-Parts-Supermicro-FPUSB813-Server-Front-Panel-2x-USB-Serial-COM-RS232-Silver-Silber.html
Fit perfectly in the place of the original floppy, com port as well on the front.
It is plug & play and no need to pray, cables, screws all fit perfectly, com2 is now connected to the front panel.  :-DD

Got the exact colour to repair the little scratches and blemish, now my scope is in a real mint condition.


I think that you should paint the USB/COM port the same color as the front panel since you have the paint.

EDIT: PS, nice job though!  :-+
« Last Edit: September 22, 2017, 05:46:39 pm by Jwalling »
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Offline eurofox

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #139 on: September 22, 2017, 04:38:52 pm »
I added as well memory, very cheap from the same shop and was shipped in 2 days door to door from Germany.  :-+

What was the real impact of adding the memory? Was it just faster operation due to less swap file access or did it make the actual scope memory depth better?

TonyG

On the Infiniium software I don't see any improvement, when using Win98 explorer or other programs it is more reactiv.
 
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Offline zucca

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #140 on: September 28, 2017, 08:28:44 am »
Manage in the bios to disable the floppy and work without problem with the floppy removed.  :clap:

Is tha an user option in the BIOS or an hack? Can you provide more details?

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Offline eurofox

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #141 on: October 03, 2017, 08:37:04 pm »
Manage in the bios to disable the floppy and work without problem with the floppy removed.  :clap:

Is tha an user option in the BIOS or an hack? Can you provide more details?

It is just tricking the setting, not really an hack but not really a setting  :-DD
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Offline JanNousiainen

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #142 on: October 13, 2017, 08:53:24 am »
Ok, made a new clean HDD and installed Windows 98 First Edition to it. Started installing 4.5 scope software to it but after creating RAM drive and rebooting nothing further happens, running the installer gives empty error message dialog. Same with 4.3. Installer packages that I have only contain three files, executable and two other files.

Should I install Win95 instead? That is what the scope came with but it had older scope SW version, started with 3.
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Offline nctnico

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #143 on: October 13, 2017, 02:49:37 pm »
Did you also install the driver for the acquisition board? How do the PCI settings look?
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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #144 on: October 13, 2017, 03:02:42 pm »
I go through the process of installing the software in this video:

https://youtu.be/L49qug1oGuo?t=5m9s

You can get all the files here:

https://1drv.ms/f/s!Amqar8_XQ9Uzj6YhN1xHdM8tQdKMOA

Read the PDF and start with the recovery image. FYI This process requires the use of a CDROM drive, TheSteve published a way around that:

Decided I should try upgrading from version 3.50 today.
As nctnico has already mentioned the built in upgrade tool only wants to read from the Magneto Optical drive. He used a hex editor to change the path so he could read the upgrade files from a USB drive. My scope has no USB ports so I tried something else.
I unpacked the 4_3_upg upgrade package on my desktop and copied the files directly to the scopes hard drive. I then booted the scope, killed the scope app and used explorer to copy the files to c:\scope\upgrade\scope\temp\
Once the files are copied you can run HP548UPG.exe directly from that directory and it will perform the upgrade.
With version 4.3 running I removed all of the files from the upgrade directory and repeated the process with the 4.5 update.
It was a pretty hassle free way to upgrade the scope. Going from version 3.5 to 4.3 easily doubles the boot time of the scope(3.5 direct to 4.5 might not as it will skip the web features). I suppose that is the tradeoff for adding the built in webserver with webcontrol. If nothing else it makes it easy to grab screen shots.

TonyG
« Last Edit: October 13, 2017, 03:05:06 pm by Tony_G »
 

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #145 on: October 31, 2017, 10:07:09 pm »
Any update? Just wondering how it turned out.

Offline Jwalling

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #146 on: November 02, 2017, 12:18:46 pm »

Back to the uphacking part. I located several resistors and decided to attach some switches after a few futile attempts to change the resistors using SMT tweezers.



The scope software can be stopped using ctrl-alt-del which opens up the task manager on Win98 and restarted from the menu so testing all the combinations could be done quickly.
Code: [Select]
R3 R2 R1 R0
-  -  X  X  54835A
X  X  -  -  54845A

X = placed, - = open

I have not found the 54846A mode but I have not included R4 in my test because I didn't spot it when looking for potential candidates. For now I'm fine with the 54845A mode.


According to the notes I have (and I think I PM'd them to you), there are only two resistors used for strapping. Was I incorrect?

(note that my crappy drawing doesn't show that R1 is also 0 Ohms.)

I have a 54846A on my bench that I'm repairing at the moment (bulging caps on the motherboard). When I get it up and running, I'll pull the ACQ board and verify the config.

When I had the motherboard pulled, I noticed that the date code on the sheet metal under the MB was dated 2001, yet the serial prefix is MY40. How can this be? :-//  I would have thought that the sheet metal should have been older, or the serial # newer...



« Last Edit: November 02, 2017, 12:21:34 pm by Jwalling »
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Offline Jwalling

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #147 on: November 02, 2017, 12:46:34 pm »
Here's the 54846A. Just two resistors need to be de-populated, so my drawing is at least correct for the 54846A.
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Offline nctnico

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #148 on: November 02, 2017, 05:02:52 pm »
I must say I tested my scope with software version 3.x so maybe that version doesn't support the 54846A  :-// But it is good to know which strapping I need alter in order to unleash more bandwidth  >:D
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Offline Jwalling

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #149 on: November 02, 2017, 06:09:41 pm »
I must say I tested my scope with software version 3.x so maybe that version doesn't support the 54846A  :-// But it is good to know which strapping I need alter in order to unleash more bandwidth  >:D

I'm not sure about that one...

Now that I'm playing with one of these again, I remember one thing I really dislike about them. They won't trigger for shit at anywhere near their rated bandwidth with a sine wave applied. This one craps out at about 1.3GHz, and I'm combining CH1 CH2 for 8GS/s. There was an excuse explanation by an Agilent Keysight support engineer (I think it was Algoss) that I bookmarked, but I guess the link didn't survive a change in their forum. Or maybe they trash the old stuff.
It was here: http://www.keysight.com/owc_discussions/thread.jspa?messageID=118580&#118580

Should have saved it locally :rant:
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Offline Jwalling

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #150 on: November 02, 2017, 06:20:45 pm »
And then I find it.
https://community.keysight.com/message/69764

I'll put it here in case it moves again. Hope I don't mess this up...

Keywords: 54835A 54845A 54846A Understanding trigger specifications.

QUESTION:
Quote
Understanding trigger specifications
Question asked by deninnh on Jan 22, 2015
Latest reply on Jan 23, 2015 by deninnh

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I've been using scopes for over 30 years up to the latest and thought I knew them fairly well.  I've purchased several high end scopes in the past and have to admit that trigger specifications were not high on my list of concerns.  They just worked !

After acquiring a personal 54846A which will not trigger above 1GHz on a clean sine wave (Agilent source), I decided I should read the spec.

It was surprising to find that trigger sensitivity for this 2.25GHz scope is only spec'd up to 1GHz.

So then what happens ?

Funny thing is that it *will* trigger on very fast events like an avalanche pulser or airborne ESD event (from a distance of course) with risetimes below 200ps.  But it just can't handle a sine wave.  I've looked at the source output and it is very clean spectrally.  On another 3GHz scope, the sine wave is perfect.

Is the scope broken?  All channels are identical in behavior.  Deleted cal files and ran full cal with no change.  Unit is very clean and has the last software version offered and also the last, fastest motherboard.

I realize that current  models have much improved triggering.  On another unmentioned brand of scopes I've always been able to trigger right up to the specified scope bandwidth before aliasing and other things kick in.   

REPLIES:

Quote
Generally, the HW Trigger BW of scopes, in the past, has been approximately half the scope BW. There are also sensitivity specifications, so depending on the signal magnitude, you can trigger on higher BW signals. Newer Agilent/Keysight scopes have a "Trigger Sensitivity" button, that can give higher BW triggering.

That said, there are also digital scopes that 'fake' a higher BW. They use a hidden 'Auto' trigger mode (which forces a trigger if there's no trigger event within a short period of time), then look for an edge near the center of the trace in SW, and move that to the middle of the display. If it happens fast enough, it is indistinguishable from a 'real' trigger. It's very hard to determine if this is being done.

You don't indicate the brand on the 3 GHz scope, or the frequency of the sinusoidal signal you used to test it, so I can't comment on that part .

Al

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    deninnh
    deninnh @ algoss on Jan 23, 2015 12:38 PM
    Hi Al,

    Thanks for the quick reply.

    I was applying a clean sine wave between 1GHz and 2.5GHz, but suspended the BW test of my "new" scope when it wouldn't get past 1GHz.  (it will actually trigger at all up to around 1.2GHz but with much jitter on the trace).

    Last night I ran the trigger sensitivity test in the service manual and it passes, but tests are only at 100MHz,  500MHz and 1GHz.

    The "other" was a TDS694C and it delivers a cleanly triggered waveform almost up to 3GHz (its BW).

    SInce there is no spec beyond 1GHz for this model, I may not have a leg to stand on for returning this scope to the dealer.

    We have a 3000X (1GHz) and 4000X (2.5GHz) at work and I noticed that the trigger spec no longer mentions at what frequency (as far as I recall).  Likewise for the other brand.  It is Y range sensitive but not frequency dependent.  These models are converting me to Agilent but my home lab budget says "old Agilent".

    So, if this scope triggers "ok" at 1GHz, would you say that was normal for the model?

    Thanks for your help.

    Den
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        algoss
        algoss Employee @ deninnh on Jan 23, 2015 12:56 PM
        Yes, I would say that since it triggers at 1GHz, it is working as specified. The fact that it's "jittery" at 1.2 GHz is proof, at least to me, that it's a real trigger, not one of the "fake" triggers I mentioned.

        The 3000X and 4000X only talk about trigger BW in terms of trigger sensitivity at different bandwidths.

        For many measurements that people are making with higher speed scopes, Edge trigger BW becomes less important. When looking at jitter, for instance, the trigger location is not part of the equation at all. The only thing that matters is the timebase, and the location of the edges.

        Al
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            deninnh
            deninnh @ algoss on Jan 23, 2015 3:27 PM
            Thanks again Al. 

            I decided to be practical about this and try it in a real world application, USB HS verification.  The trigger was good enough but of less importance since the test is done on data from a single sweep, triggered by a pulse width condition.

            It worked flawlessly and blows away the old TDS in terms of ease of use and fast storage (good old 1GB flash drive under Win98).

            Den
« Last Edit: November 02, 2017, 06:45:00 pm by Jwalling »
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Offline nctnico

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #151 on: November 02, 2017, 06:23:18 pm »
I'm aware of that limitation. It still is a good buy IMHO. I bought the 54835A specifically for looking at digital signals and it does that OK. It already has done some work to pay for itself.
« Last Edit: November 02, 2017, 06:24:52 pm by nctnico »
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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #152 on: November 03, 2017, 11:12:19 pm »
Here's the 54846A. Just two resistors need to be de-populated, so my drawing is at least correct for the 54846A.

I have a fully working 54845A that pass all test and calibrate without problem and I did the change to make it a 54846A.
It detect that it is a 54846A but testing give a lot of error and finally crash!

This mean that software is different and maybe attenuators and other parts …

It could be as well that during installation of the software that is encapsulated in the installation software different versions are installed depending of the resistor selecting the model.
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Offline Jwalling

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #153 on: November 04, 2017, 09:43:20 am »
Here's the 54846A. Just two resistors need to be de-populated, so my drawing is at least correct for the 54846A.

I have a fully working 54845A that pass all test and calibrate without problem and I did the change to make it a 54846A.
It detect that it is a 54846A but testing give a lot of error and finally crash!

This mean that software is different and maybe attenuators and other parts …

It could be as well that during installation of the software that is encapsulated in the installation software different versions are installed depending of the resistor selecting the model.

It's not the software. I have one Symantec Ghost image that works in all the scopes in this series with the FIC motherboard.
The scopes are 54810A, 54815A, 54820A 54825A, 54835A, 54845A, and 54846A.
Jay

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Offline eurofox

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #154 on: November 04, 2017, 11:27:41 am »
Here's the 54846A. Just two resistors need to be de-populated, so my drawing is at least correct for the 54846A.

I have a fully working 54845A that pass all test and calibrate without problem and I did the change to make it a 54846A.
It detect that it is a 54846A but testing give a lot of error and finally crash!

This mean that software is different and maybe attenuators and other parts …

It could be as well that during installation of the software that is encapsulated in the installation software different versions are installed depending of the resistor selecting the model.

It's not the software. I have one Symantec Ghost image that works in all the scopes in this series with the FIC motherboard.
The scopes are 54810A, 54815A, 54820A 54825A, 54835A, 54845A, and 54846A.

It is working in the 548446A mode not calibrated, I did not check the performance to check if the modification work, the software ask to do a calibration what I try and fail on all channels, I start again with a test and got a lot of errors and finally the software crash.
It cross my mind to replace the 0 ohm resistor with a switch wired to the back of the scope because it is not a good idea to "play" with the board due to EMC and connector issues but just put the resistor back, 1.5Ghz is not that bad  :popcorn:
eurofox
 

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #155 on: November 10, 2017, 10:38:13 pm »
In some miraculous way, my Agilent 54845A turned into 54845B (at least so it is now shown).



I made a motherboard update and a software update v.4.5 for 54845B. I tried different versions of software, but only with this I got success.

Previously, there was an Atlas PCI-III Series 757 motherboard based on Socket 7 and AMD K6-2 300 MHz processor and 64 MB RAM.

Now the most advanced motherboard for AT-form factor with Intel 440BX chipset and Socket 370, with 133MHz bus, where the Coppermine core Pentium III processor can be installed, up to 1133MHz (or with a small upgrade of Tualatin 1400MHz) and 3x256 MB of RAM max.

The new motherboard is designated Tomato (ZIDA) 60-cbxict1
Next to her on the photo is an old motherboard Atlas Series 757


I also had to replace the Ethernet controller for the PCI slot








At the moment I used a P III - 733MHz processor.
Subjectively, now I noticed a significantly smaller loss of the frequency of updates to the oscillogram in the mode of activation of measuring functions, than it was before.







p.s.
Now I found information that the manufacturer installs in the 54845B motherboard "VP22 Motorola" (Socket 370) and processor Celeron/Pentium III - 866 (Coppermine). Thus, we can assume that I received the same without changing the form factor AT. The only difference is that I still do not have a built-in CD-ROM, but it's not required too often.
« Last Edit: November 11, 2017, 02:44:32 pm by Converter »
 

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #156 on: November 11, 2017, 10:56:41 am »
In some miraculous way, my Agilent 54845A turned into 54845B (at least so it is now shown).

I made a motherboard update and a software update v.4.5 for 54845B. I tried different versions of software, but only with this I got success.

Previously, there was an Atlas PCI-III Series 757 motherboard based on Socket 7 and AMD K6-2 300 MHz processor and 64 MB RAM.

Now the most advanced motherboard for AT-form factor with Intel 440BX chipset and Socket 370, with 133MHz bus, where the Coppermine core Pentium III processor can be installed, up to 1133MHz (or with a small upgrade of Tualatin 1400MHz) and 3x256 MB of RAM max.

The new motherboard is designated Tomato (ZIDA) BXv98-CU/v693


Are you sure about the new motherboard part #? I ask because the images for it all show a Via chipset: https://www.google.com/search?q=BXv98-CU/v693&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwit6P26rbbXAhWKy4MKHSNOBswQsAQILg&biw=1518&bih=934

One on eBay has a Via chipset as well: https://www.ebay.com/itm/Tomato-Board-ZIDA-BXv98-CU-V693-Socket-370-Motherboard-4-PCI-2-ISA-AGP-slots/182114467065?hash=item2a66de3cf9:g:JG4AAOSwIjNXJcE3

Jay

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #157 on: November 11, 2017, 02:41:54 pm »
Hi Jwalling,
It looks like there really is a ZIDA motherboard with exactly the same external design, but with VIA chipsets. But on my board a set of Intel chips is actually installed. On my board there is only an inscription: 60-cbxict1 30-00 (I edited my previous post).
The manual was not found, but the display shows: -440BX-
BIOS allows to overclock the processor bus up to 150 MHz, which corresponds to the specification 440BX.
« Last Edit: November 11, 2017, 02:47:06 pm by Converter »
 
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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #158 on: November 11, 2017, 04:51:28 pm »
Hi Jwalling,
It looks like there really is a ZIDA motherboard with exactly the same external design, but with VIA chipsets. But on my board a set of Intel chips is actually installed. On my board there is only an inscription: 60-cbxict1 30-00 (I edited my previous post).
The manual was not found, but the display shows: -440BX-
BIOS allows to overclock the processor bus up to 150 MHz, which corresponds to the specification 440BX.

Thanks for the clarification. Have you thought about upgrading it to a 2.25GHz 54846A/B?  :popcorn:
Jay

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #159 on: November 11, 2017, 05:13:34 pm »
Thanks for the clarification. Have you thought about upgrading it to a 2.25GHz 54846A/B?  :popcorn:

Yes, I want to follow your example. In any case, I will try. Has someone succeeded in the calibration procedure after changing 54845 to 54846?

I also have a couple of questions: how to get access to the Windows desktop in this device? What drivers are needed to use usb flash memory to save screenshots in it?
« Last Edit: November 11, 2017, 05:22:39 pm by Converter »
 

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #160 on: November 11, 2017, 06:54:23 pm »
Thanks for the clarification. Have you thought about upgrading it to a 2.25GHz 54846A/B?  :popcorn:

Yes, I want to follow your example. In any case, I will try. Has someone succeeded in the calibration procedure after changing 54845 to 54846?

I also have a couple of questions: how to get access to the Windows desktop in this device? What drivers are needed to use usb flash memory to save screenshots in it?

I did the removal of the resistor to change my 54845 to 54846 but many errors in test and crash finally the test program.

Calibration attempt fail immediately.

Windows function is easy just by "Ctl key" and "esc key" on the keyboard.

I got my usb working but don't think I used a special driver, I suppose it is available in Windows 98.

I collected a usb driver that I find just by google somewhere on the net but did not use it.


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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #161 on: November 11, 2017, 06:54:39 pm »
Thanks for the clarification. Have you thought about upgrading it to a 2.25GHz 54846A/B?  :popcorn:

Yes, I want to follow your example. In any case, I will try. Has someone succeeded in the calibration procedure after changing 54845 to 54846?

I also have a couple of questions: how to get access to the Windows desktop in this device? What drivers are needed to use usb flash memory to save screenshots in it?

I think you'll be the first to upgrade to a 54846 successfully if it works!

Is this the right manual? http://www.elhvb.com/mboards/zida/manuals/CreatN10.zip
(Manual covers a slot processor version as well)

There is an "upgrade" for Win98 USB thumb drive support out there. It does work on these scopes.
It's been quite awhile since I did it, but IIRC it was this link that worked for me: http://www.technical-assistance.co.uk/kb/usbmsd98.php

The desktop on these is weird, I've never been able to customize it, but I didn't spend much time on it either.
I don't think you can minimize the scope app, only kill it with CTRL ALT DEL or possibly with CTRL ESC and end it from the taskbar.

Jay

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #162 on: November 11, 2017, 07:20:58 pm »
Jay, your manual seems to fit (page 14).

I tried to reset the jumper, as you described. It really does now show 54846B. However, the calibration was not successful for each of the 4 channels. I do not know what is the reason, I think there are hardware differences that do not allow to make an upgrade 54845 to 54846 (or fine-tune the input amplifiers).

eurofox, thanks, I'll try to do it. I correctly understand that now you have the opportunity to use a usb flash to save the screenshot files?
« Last Edit: November 11, 2017, 07:38:48 pm by Converter »
 

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #163 on: November 11, 2017, 11:01:02 pm »
Jay, your manual seems to fit (page 14).

I tried to reset the jumper, as you described. It really does now show 54846B. However, the calibration was not successful for each of the 4 channels. I do not know what is the reason, I think there are hardware differences that do not allow to make an upgrade 54845 to 54846 (or fine-tune the input amplifiers).

eurofox, thanks, I'll try to do it. I correctly understand that now you have the opportunity to use a usb flash to save the screenshot files?

Yes I have replaced the floppy disk by 2 usb connectors and I can copy files.
eurofox
 

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #164 on: November 12, 2017, 12:50:58 am »
Agilent program is more convenient to close "CTRL" + "F4".
In the original set, Windows did not have a suitable driver for flash memory. I installed this driver: http://www.technical-assistance.co.uk/kb/win98fe-usb-mass-storage-drivers.php
Now there's a removable disk (:E) and it works great.

Maybe someone managed to upgrade to Windows 2K?
« Last Edit: November 12, 2017, 12:59:47 am by Converter »
 

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #165 on: November 12, 2017, 11:39:29 am »
Maybe someone managed to upgrade to Windows 2K?

That's the one thing I think is impossible. The problem is that there's no 2K drivers for the acquisition controller.

It's surprising that the 54845A can't be upgraded to a working 54846A. All the magic in these scopes are in the attenuator assemblies and A/D converters. Both models use the same parts - the A/D converters are part #1NB7-8353 and the Attenuator modules are 54512-63402 for both models. There must be some other minor modification needed...

I still have this 54846A in my possession, and I have some scrap 54845A ACQ boards laying around. Maybe I'll do a in-depth comparison between the two today if I get a chance.
Jay

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #166 on: November 12, 2017, 12:50:38 pm »
Curiosity got the better of me and I couldn't resist waiting.

Here's another difference I found on the solder side under PGA device U91

Two resistors are not installed on the 54846A!
« Last Edit: November 12, 2017, 12:52:45 pm by Jwalling »
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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #167 on: November 12, 2017, 02:00:39 pm »
That's the one thing I think is impossible. The problem is that there's no 2K drivers for the acquisition controller.
There is one guy on this forum who was able to modify the WinXP drivers for the oscilloscope LeCroy WavePro7k, that they now work in Win7. I do not exclude anyone could do or have already done similar and the drivers Agilent Win98.

Quote
It's surprising that the 54845A can't be upgraded to a working 54846A. All the magic in these scopes are in the attenuator assemblies and A/D converters. Both models use the same parts - the A/D converters are part #1NB7-8353 and the Attenuator modules are 54512-63402 for both models.

Yes, I'm also surprised at this. I tried to restart the calibration 3 times and always got a negative result. In this case, the test of the input channels gave an error almost instantly, as if he had seen forgery in advance.

Quote
Here's another difference I found on the solder side under PGA device U91
Two resistors are not installed on the 54846A!

Are you sure that the presence of these resistors is essential? It would be good to check this: remove these resistors and try to do the calibration procedure without them. If you get the same negative result as I do, it will be a breakthrough (by the way, what is the value of these resistors?).
« Last Edit: November 12, 2017, 02:02:37 pm by Converter »
 

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #168 on: November 12, 2017, 02:53:46 pm »
Are you sure that the presence of these resistors is essential? It would be good to check this: remove these resistors and try to do the calibration procedure without them. If you get the same negative result as I do, it will be a breakthrough (by the way, what is the value of these resistors?).

What I'm saying is that the 54846A does not have the resistors installed so there's nothing to remove. Your 54845A (if I'm right) has them installed. They are 261 Ohms in the 54845A.

Looking a bit closer now; there may be a little more to this:
The other two resistors right next to those that are installed in both boards have different values as well.
On the 54845A they are 90.9 Ohms (marked in blue). In the 54846A (also marked in blue) they are 68.1 Ohms.
Jay

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #169 on: November 13, 2017, 02:28:30 am »
Are you sure that the presence of these resistors is essential? It would be good to check this: remove these resistors and try to do the calibration procedure without them. If you get the same negative result as I do, it will be a breakthrough (by the way, what is the value of these resistors?).

What I'm saying is that the 54846A does not have the resistors installed so there's nothing to remove. Your 54845A (if I'm right) has them installed. They are 261 Ohms in the 54845A.

Looking a bit closer now; there may be a little more to this:
The other two resistors right next to those that are installed in both boards have different values as well.
On the 54845A they are 90.9 Ohms (marked in blue). In the 54846A (also marked in blue) they are 68.1 Ohms.

I made changes according to your description. Removed 2 resistors 261 Ohms and replaced 2 resistors 91 Ohm by 68 Ohm. Unfortunately, after this absolutely nothing has changed. The calibration process is still without success. So I returned everything to its original state.
 

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #170 on: November 13, 2017, 06:55:35 am »
To me it seems these resistors are some kind of termination network for signals so it doesn't surprise me that nothing changed.

I think it is time to take hires pictures of boards from the 845 & 846 and subtract them in photo editing software to highlight the differences.
« Last Edit: November 13, 2017, 06:58:18 am by nctnico »
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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #171 on: November 26, 2017, 06:05:04 pm »
I investigated the bandwidth of my HP54845 in the factory settings. It seems that it has more than 2 GHz without any upgrade. As the source of the broadband signal, I used an industrial noise generator on avalanche-passing diodes (0.4-4 GHz). This is a very primitive device and there is a noticeable frequency unevenness in the spectrum of the generated signal. Indeed, in its generated spectrum there is a rise in the region of 100-300 MHz and a dip at 1.8 GHz. Nevertheless, this allows us to approximately estimate the bandwidth of the oscilloscope.
« Last Edit: November 26, 2017, 06:09:46 pm by Converter »
 

Offline nctnico

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #172 on: November 26, 2017, 06:09:40 pm »
The measurements I did showed my uphacked 54845 is just right by looking at the risetime. Unfortunately these scopes won't trigger on signals over 1GHz so maybe your noise measurement shows a more complete picture.
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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #173 on: November 26, 2017, 06:13:18 pm »
I added screenshots.
Unfortunately at the moment I do not have a high-quality microwave generator to make measurements more accurately (yes, I know about the limitations of the trigger). But a rough estimate can be made using this noise generator. There were used 2 scales: 10 dB/div and 5 dB/div. I have roughly noted positions with cursors corresponding to a -3 dB change in the level. This corresponds to a bandwidth of 2.127 GHz.
« Last Edit: November 26, 2017, 07:37:55 pm by Converter »
 

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #174 on: November 26, 2017, 07:00:39 pm »
This oscilloscope HP 54845 is not inferior to the bandwidth of my LeCroy WavePro7200.
For comparison, I attach several measurements made in the same way with other of my oscilloscopes (FFT 10dB/div):
LeCroy WavePro7200;
LeCroy WavePro7300A;
LeCroy DDA-120;
LeCroy LC564DL;
Tektronix TDS5054B.

I also want to note that the HP 54845 demonstrated a restart speed of the trigger, which reaches 92 us (in the case of the easiest acquisition settings). This corresponds to processing 11K oscillograms per second, which is 30-50 times faster than all oscilloscopes from my list above (3-5 ms minimum). Faster than this, only the FastACQ-mode in Tek 5054 (7 us) - but this mode is not fully functional, and my analog oscilloscope LA354 (which reaches 1 us).
« Last Edit: November 26, 2017, 09:55:22 pm by Converter »
 

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #175 on: November 26, 2017, 10:06:07 pm »
Maybe someone managed to upgrade to Windows 2K?

That's the one thing I think is impossible. The problem is that there's no 2K drivers for the acquisition controller.

There must be an upgrade kit that consists of one or two RAM modules, an XP license and
obviously, the drivers for XP. So, they must exist somewhere.

N5383A Infiniium Performance Upgrade kit   for 54846B
win98 ? XP pro   256MB ? 512 MB  $495

I have a 54846B that booted increasingly slow and finally the disk showed many read errors.
I replaced the 20 G unit by a 80G unit that I used to have in a Dell Laptop and reserved
some of the space for a Linux Partition. (Knoppix) That made it easy to setup the new Win98.
For the fun of it, I even succeded to run Libre Office on the 54846B, but it was slow as
molasse.  Somewhere I have a screen shot.  :)

regards,
Gerhard
 

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Offline nctnico

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #177 on: November 26, 2017, 10:29:43 pm »
Maybe someone managed to upgrade to Windows 2K?
That's the one thing I think is impossible. The problem is that there's no 2K drivers for the acquisition controller.
There must be an upgrade kit that consists of one or two RAM modules, an XP license and
obviously, the drivers for XP. So, they must exist somewhere.

N5383A Infiniium Performance Upgrade kit   for 54846B
win98 ? XP pro   256MB ? 512 MB  $495
I have come to the same conclusion. Windows XP runs OK on my 54845 and the software should be compatible as well but the driver for the acquisition card is missing. I have pulled all my Google-fu tricks and then some but I have not been able to find the drivers. I wish someone would make the XP drivers available because Windows XP has better support for USB devices.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #178 on: November 26, 2017, 10:43:13 pm »
From <  http://www.probe.co.il/Documents/Infiniium%20548xx%20Series%20probe%20accessories%20and%20option.pdf  >

It seems this applies to the software for Infiniium 54830, -31, -32. I'm not sure, but I think that it uses advanced ACQ board and faster data transfer interface. It may be that the software for 54830 (1) is not compatible with the oscilloscopes 54825, -35, -45(6). You could check this by installing the disk image for 54830. A link to the archive containing the disk image  I saw somewhere in this topic.
« Last Edit: November 26, 2017, 10:57:47 pm by Converter »
 

Offline Jwalling

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #179 on: November 27, 2017, 10:39:07 am »
Maybe someone managed to upgrade to Windows 2K?
That's the one thing I think is impossible. The problem is that there's no 2K drivers for the acquisition controller.
There must be an upgrade kit that consists of one or two RAM modules, an XP license and
obviously, the drivers for XP. So, they must exist somewhere.

N5383A Infiniium Performance Upgrade kit   for 54846B
win98 ? XP pro   256MB ? 512 MB  $495
I have come to the same conclusion. Windows XP runs OK on my 54845 and the software should be compatible as well but the driver for the acquisition card is missing. I have pulled all my Google-fu tricks and then some but I have not been able to find the drivers. I wish someone would make the XP drivers available because Windows XP has better support for USB devices.

I'm certain that XP was never used in these first generation Infiniium scopes: 54810A through 54825A, 54835A, 54845A, and 54846A.
B versioned scopes are another matter, as are the 54830 and 54850 series...

If you really want better/native USB support, Win ME (yuck) is certainly possible.  >:D
Jay

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #180 on: November 27, 2017, 05:30:42 pm »
From the upgrade PDF these models at some point supported XP:

Quote
For models 54830B, 54830D, 54831B, 54831D, 54832B, 54832D, 54833A, 54833D

These models were originally released with the Windows 98 operating system. Newer units and
upgraded older units run Windows XP.

You could try copying the drivers from the ghost image locations for the Win98 bits(c:\windows\system32\drivers and c:\windows\inf directories). If the driver is a full 32 bit driver then there is a chance that it will work under Windows XP. Alternatively you could do the same thing with the WinXP image (c:\windows\system32\drivers )assuming acquisition card didn't change much (the driver might include support for the older cards)

TonyG
[Edited for clarity and my misreading of the PDF]
« Last Edit: November 27, 2017, 05:52:48 pm by Tony_G »
 

Offline nctnico

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #181 on: November 27, 2017, 08:24:13 pm »
You can't use Win98 drivers on XP because the driver model is completely different.
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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #182 on: November 28, 2017, 02:54:18 am »
You can't use Win98 drivers on XP because the driver model is completely different.

That isn't completely correct.

Windows Driver Model (WDM) was introduced in Win98. The previous driver model was VxD and it is also supported in Win98. That said, the driver in the WinXP image may be based on WDM and may be able to be used on Win98 - WinXP introduced new WDM features so a WinXP WDM driver may not work on Win98/Win2K but a Win98/Win2K WDM driver will work on WinXP.

Of course the driver could also be based on Windows Driver Foundation and thus be basically XP and up (ignoring UMDF & KMDF distinctions).

So there is a chance that the driver from the XP image will work on the Win98 one.

TonyG

« Last Edit: November 28, 2017, 02:57:27 am by Tony_G »
 

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #183 on: December 04, 2017, 09:20:40 am »
I think the naming scheme used by Agilent/HP for the 54XXX series are confusing (546XX and 548XX has some models that might be mistaken as the other series).

For Infiniiums, 54830 series means 5483X where X is 1 or 2. They are the ones using VP22 motherboard that you can modernize to Win XP.

548X5 is the high bandwidth old Infiniium with the same PC software as the 5481X, 5482X that are hopelessly Windows 98. The 54835 you are talking about belongs to the same class as 54845 and 54855, which has nothing to do with the so-called '54830' series.

Hope it helps.
« Last Edit: December 04, 2017, 09:23:36 am by dogbert »
 

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #184 on: December 04, 2017, 11:10:08 am »
I think the naming scheme used by Agilent/HP for the 54XXX series are confusing (546XX and 548XX has some models that might be mistaken as the other series).

For Infiniiums, 54830 series means 5483X where X is 1 or 2. They are the ones using VP22 motherboard that you can modernize to Win XP.

548X5 is the high bandwidth old Infiniium with the same PC software as the 5481X, 5482X that are hopelessly Windows 98. The 54835 you are talking about belongs to the same class as 54845 and 54855, which has nothing to do with the so-called '54830' series.

Hope it helps.

That's not quite correct. The 54850 series (54853A, 54854A, and 54855A) use the newer VP22 motherboard as well and came with XP. I know, because I just finished a repair on a 54855A for a  customer.

EDIT: I think a good way to tell whether they are first or second generation (or later) Infiniiums, is if it says "Megazoom" on the front panel.
« Last Edit: December 04, 2017, 11:13:49 am by Jwalling »
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Offline dogbert

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #185 on: December 10, 2017, 06:11:04 am »
I don't recall mentioning anything about 54850 series on my post, but I know the difference between the VP22 boards can be removed by upgrading the BIOS supplied by Agilent.

Nonetheless, I agree with you that the best way to tell which generation it is by whether it has Megazoom. Also note that the 54830 series might come with an ADlink motherboard instead of Motorola VP22. The ADlink board has only 3 PCI slots that you have to use the combo card if you don't want to lose the GPIB. The downside is that the combo card does not work on old acquisition board, and it's not easy to tell without trial and error (I don't have a list of serial number ranges to tell which Acq board works with the combo card).
 

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #186 on: December 13, 2017, 02:27:03 am »
Update on my scope:
USB: My motherboard support 2 USB connections on the motherboard.

I bought this unit: http://electromyne.de/Server-Parts-Supermicro-FPUSB813-Server-Front-Panel-2x-USB-Serial-COM-RS232-Silver-Silber.html
Fit perfectly in the place of the original floppy, com port as well on the front.
It is plug & play and no need to pray, cables, screws all fit perfectly, com2 is now connected to the front panel.  :-DD

Manage in the bios to disable the floppy and work without problem with the floppy removed.  :clap:

I added as well memory, very cheap from the same shop and was shipped in 2 days door to door from Germany.  :-+

Got the exact colour to repair the little scratches and blemish, now my scope is in a real mint condition.

Install a pdf printer emulator.  :popcorn:

Now hunting for probes.  |O

I made a plastic overlay for the usb front panel (https://www.ebay.com/itm/202029998994). It was easy and now it looks like the original part. The whole process is shown in the photo.











« Last Edit: December 13, 2017, 02:33:29 am by Converter »
 
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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #187 on: December 28, 2017, 02:55:54 am »
I recommend using the trackball, as Agilent suggests.
I found this part (with the Compaq logo) at a very low price in China. I bought 2 pcs in almost new condition for 99 yuan per piece (approximately $ 15).
One of them I dyed in the color of the front panel of the oscilloscope, using colors of two shades of gray. In reality, it looks more harmonious than in the photo and most importantly, that it does not require free space on the table.
« Last Edit: December 28, 2017, 03:42:39 am by Converter »
 

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #188 on: December 28, 2017, 04:19:01 am »
In the supplied software, the Windows desktop is locked. If you want to have the usual access to the desktop in Windows 98 you can do this only by editing the system registry. You can use the built-in utility Registry Editor. For this go to "start->run" and enter "regedit". You need to change the value of NoDesktop to 0, as on the attached photo. Address in the register: HKEY_CURRENT_USER\Software\Microsoft\Windows\Current Version\Policies\Explorer\NoDesktop

I have added usb ports to the front panel, so I no longer use a floppy device (drive A, B). However, despite deactivating them in Bios, I've seen drives A and B in the file manager.
You can also hide them, if you do not use them, using the System Registry setting. Address in the register:
HKEY_CURRENT_USER\Software\Microsoft\Windows\Current Version\Policies\Explorer\NoDrives
Depending on the value, different drive letters are hidden, 00 00 00 00 - none is hidden.
Value 1 - hides disk A
Value 2 - hides the disk B
Value 3 - hides disks A and B.


« Last Edit: December 28, 2017, 04:20:56 am by Converter »
 

Offline Gerhard_dk4xp

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #189 on: December 28, 2017, 04:42:51 am »
My 54846B motherboard also has a normal floppy controller, in addition
to the exotic 120MB combi drive. That could help if the special drive is
defective and cannot be found as a replacement part. The Plug is directly
at the front side of the motherboard.

What drivers do I need for USB sticks under Win98? I could live with
the built-in interfaces on the back side and an external extension cable.
Sticks do not work in my configuration.

regards, Gerhard
 

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #190 on: December 28, 2017, 05:22:43 am »
I found 2 processor Pentium III 1000 MHz (see photo). One of them is a later release and has a heat-distributing cover. However, they are both with the Coppermine core, so I do not need to modify the socket and change the Bios to switch i440BX to Tualatin.
Both processors excellently bother at a bus frequency of 140 MHz, but not one of them could not work reliably at 150 MHz.

For cooling, I bought a cooler intended for Socket 462 (Socket A). When it was delivered, it was twice the size of what was in my Socket 370, but there was not the slightest obstacle to its easy installation in the motherboard.
It has a bifurcated bracket attached to the 4 protrusions of the socket, in contrast to the radiator for socket 370, which is attached to only 2 ledges. So it seems that this is kept much more stable.

The image from the hard disk was successfully transferred to the IDE SSD and the partition was increased to 16 GB using the alignment operation. This inexpensive drive showed sequential read speed of about 85MB/s, which is 1 order of magnitude greater than the old disc, but the most bottleneck here is Hard Disk Controller - PIO Mode 5/DMA Mode 3 (33.3MB/S).
Probably a better solution is to use a separate expansion card in a PCI slot with a sata controller. But then the loading of an individual BIOS for such a controller will be added during the start of the computer, which can again worsen the start time of the device.


« Last Edit: December 28, 2017, 02:29:45 pm by Converter »
 

Offline Converter

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #191 on: December 28, 2017, 05:29:13 am »
What drivers do I need for USB sticks under Win98? I could live with
the built-in interfaces on the back side and an external extension cable.
Hi,
I used these:
https://www.eevblog.com/forum/testgear/agilent-54835a-scope-(4-channel-1ghz-4gss)-repair-uphack/msg1347291/#msg1347291
 

Offline JanNousiainen

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #192 on: January 04, 2018, 12:33:32 pm »
Well I got mine working again with clean install of 3.5 recovery CD:)

I had to borrow Mac G5 DVD drive that had IDE interface and use Rasp Pi GPIO extender ribbon cable to connect it to scope. After that it was smooth sailing and now my unit runs on Windows 98. I might install later updates if I feel brave someday.

Only problem was in calibration. I used too long BNC- BNC cable (1.5 - 2 m) to connect channels to AUX OUT and calibration would fail. I switched to 25 cm long better quality SMA + BNC adapter - BNC cable and no problems after that.

Now I just need to figure what I want to do with the scope...
"I have approximate knowledge of many things."
 

Offline Converter

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #193 on: January 04, 2018, 03:44:59 pm »
Only problem was in calibration. I used too long BNC- BNC cable (1.5 - 2 m) to connect channels to AUX OUT and calibration would fail. I switched to 25 cm long better quality SMA + BNC adapter - BNC cable and no problems after that.
It's strange. I used to calibrate the cables of different lengths and the process is always successful. I know that the instruction requires a short cable, just wondering, for what reason is the cable length important here?

Quote
Now I just need to figure what I want to do with the scope...
You, like me, want to convert oscilloscope to Windows XP :)
« Last Edit: January 04, 2018, 03:47:10 pm by Converter »
 

Offline Tony_G

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #194 on: January 04, 2018, 05:34:01 pm »
for what reason is the cable length important here?

The cable length will impact the rise time of the calibration pulses.

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #195 on: January 04, 2018, 05:43:24 pm »
for what reason is the cable length important here?

The cable length will impact the rise time of the calibration pulses.

TonyG
But more importantly are differing propagation delays between channels with different length cables.. Scopes will detect this and if it's outside predefined parameters the calibration will fail.
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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #196 on: January 04, 2018, 05:58:54 pm »
But more importantly are differing propagation delays between channels with different length cables.. Scopes will detect this and if it's outside predefined parameters the calibration will fail.

Yes - Don't change cables in the middle of the calibration. That is technically known as 'Bad'.

That said, I don't believe that this scope (54845A) uses the calibration signal to perform any analysis of propagation delay. According to the service manual the scope only self calibrates for channel sensitivity, voltage offsets, and trigger parameters (hold-off etc not being dependent on the propagation time through the cable but on the accuracy of the internal time base).

Anyway, as Tautech noted, if the cable is too long it will impact all of these values and cause the calibration to fail even though the underlying scope HW is working correctly.

TonyG
« Last Edit: January 04, 2018, 06:06:11 pm by Tony_G »
 
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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #197 on: January 04, 2018, 06:35:11 pm »
It seems that this depends more on the quality of the cable and the connectors in the impedance matched coaxial line. I have an example when a short BNC connector (0.3m) shows a worse bandwidth than a high quality one with a length of 1.5m (I see it by the result of the rise time). However, all of them give a positive result of HP 54845 calibration. So, if the delay time does not matter and you have a high-quality cable, then this should not be a problem.
 

Offline JanNousiainen

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #198 on: January 04, 2018, 07:18:36 pm »
My first cable was thick and black (RG58?) with BNC connectors, from china of course.

Second cable was thin and coppery (RG316?) but also about max 1/5th of length of first one. I think this one was much better quality compared to first one.
"I have approximate knowledge of many things."
 

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #199 on: January 04, 2018, 08:24:16 pm »
Yes, RG58 cable is not good for this case.
 

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #200 on: January 22, 2018, 06:57:16 pm »
Hello everyone.
Now I was able to install a 1400MHz P-III Tualatin processor. This required editing the BIOS (a lot of attempts before the success).


To install it, you needed an adapter PCB.


Of some tests, its performance is higher than the original K6-2-300 in 4 times. It is even ahead of some P4.


I also added preventively small radiators to the power converter.


I was surprised when I measured the frequency of the trigger restart. This amounted to 54 microseconds (18-19 kHz). This is many times higher than the one declared in the datasheet of 2 kHz. In the photo - the impulses start trigger 54845, measured using LeCroy.


Indeed, I see a lot of "threads" this device processes in real-time mode.



« Last Edit: January 22, 2018, 10:06:05 pm by Converter »
 

Offline nctnico

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #201 on: January 22, 2018, 07:35:19 pm »
Hello everyone.
Now I was able to install a 1400 MHz P-III processor. This required editing the BIOS (a lot of attempts before the success).

So cool!  :-+ :-+
I'd love to get some extra performance. Unfortunately it seems yours has a different motherboard than mine so your BIOS is likely not to work on my scope.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #202 on: January 22, 2018, 09:22:52 pm »
nctnico, what is your motherboard? It seems to me that any motherboard that supports the Coppermine core is suitable for upgrading BIOS. I can give contacts to the person who will help you.
« Last Edit: January 22, 2018, 09:24:25 pm by Converter »
 

Offline nctnico

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #203 on: January 22, 2018, 09:27:53 pm »
nctnico, what is your motherboard? It seems to me that any motherboard that supports the Coppermine core is suitable for upgrading BIOS. I can give contacts to the person who will help you.
My motherboard is the original VA503-A Super Socket 7 motherboard but I now realise that you must have changed the motherboard.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #204 on: January 22, 2018, 10:02:40 pm »
My motherboard is the original VA503-A Super Socket 7 motherboard but I now realise that you must have changed the motherboard.
Yes, as I wrote in this thread, I installed the ZIDA TomatoBoard ZX98-CT motherboard (for Socket 370) and it was immediately successful with the HP54845A (with the Coppermine processor). It took only a little effort to translate it into a Tualatin processor. These Baby-AT motherboards today are very cheap, so it makes sense to buy and install them. I buy them in my region for only $4-6.
I also got the motherboard PC Partner BSBS3-T871B http://support.pcpartner.com/support/bios/i810.htm (see attached photo). It has a newer intel® 810 series chipsets. This is better than chipset Intel 443BX/ZX in that it supports IDE Ultra DMA4-66 (and not only DMA2-33).
« Last Edit: January 22, 2018, 10:08:08 pm by Converter »
 

Offline nctnico

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #205 on: January 23, 2018, 01:19:52 pm »
I'm wondering if an ATX motherboard will fit if the printer port is removed and whether the software works without the GPIB card. I have an old PC with a Core2 duo 2GHz-ish in it which I wouldn't mind butchering. It will need the extra 12V ATX plug though but I think I can botch something.
« Last Edit: January 23, 2018, 01:33:13 pm by nctnico »
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #206 on: January 23, 2018, 02:11:58 pm »
1. I think it's possible to use an ATX motherboard of suitable width if you are ready for a lot of work with a rasp :) .
2. You can remove the GPIB controller card right now to check this. You can also try to use such a controller for the PCI interface.
3. The power connector can be used from any unnecessary power supply, the starting PIN can be activated permanently, or via a delay circuit.
« Last Edit: January 23, 2018, 02:14:25 pm by Converter »
 

Offline free_electron

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #207 on: January 23, 2018, 03:22:52 pm »
machines work fine without the gpib
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Any comments, or points of view expressed, are my own and not endorsed , induced or compensated by my employer(s).
 
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Offline nctnico

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #208 on: January 23, 2018, 03:29:03 pm »
1. I think it's possible to use an ATX motherboard of suitable width if you are ready for a lot of work with a rasp :) .
I'm just hoping the keyboard connector lines up a bit. I'll probably just desolder the plugs which stick out of the motherboard if I go ahead with this.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #209 on: February 23, 2018, 01:43:24 pm »
Hello dear members, I currently have an issue with the GAL16vd8 chip on the scope. Next to the BIOS and RTC. Its fried and I cannot retrieve any info. Nor would the scope boot. Does anybody have the option to get the code from this chip labeled 1996 ami 73xx PODxxx and email it to me. thanks for your reply,
If you need pictures or else, please let me know, Best regards,
Nicolas
 

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #210 on: February 23, 2018, 03:15:55 pm »
I just put a low offer in for an Agilent 54835A on eBay "parts or not working" status - screen shows nothing.  Maybe they'll accept, maybe not.  What should I be looking for?  Is the Agilent 54845A a whole lot better?
I'd like to make the world a better place but they won't give me the source code
 

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #211 on: February 23, 2018, 03:52:34 pm »
I just put a low offer in for an Agilent 54835A on eBay "parts or not working" status - screen shows nothing.  Maybe they'll accept, maybe not.  What should I be looking for?  Is the Agilent 54845A a whole lot better?
You can uphack the '835A to an '845A by changing a few resistors. You get double the samplerate on all channels and 1.5GHz bandwidth if you only use channel 1 and 3.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline Jwalling

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #212 on: February 23, 2018, 05:01:47 pm »
Hello dear members, I currently have an issue with the GAL16vd8 chip on the scope. Next to the BIOS and RTC. Its fried and I cannot retrieve any info. Nor would the scope boot. Does anybody have the option to get the code from this chip labeled 1996 ami 73xx PODxxx and email it to me. thanks for your reply,
If you need pictures or else, please let me know, Best regards,
Nicolas

I may be able to help if it's not protected, and my programmer supports the device (I think it does). I'll follow up tomorrow...
In the meantime, please post the VIN # from the rear of the scope.
Jay

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #213 on: February 23, 2018, 06:41:15 pm »
My low ball offer was declined, so be it.  I'm not paying $900 for an as-is broken scope + $100 shipping.
I'd like to make the world a better place but they won't give me the source code
 

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #214 on: February 23, 2018, 06:47:10 pm »
My low ball offer was declined, so be it.  I'm not paying $900 for an as-is broken scope + $100 shipping.

Run fast and far at $900.00.
VE7FM
 

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #215 on: February 23, 2018, 07:05:22 pm »
I just put a low offer in for an Agilent 54835A on eBay "parts or not working" status - screen shows nothing.  Maybe they'll accept, maybe not.  What should I be looking for?  Is the Agilent 54845A a whole lot better?

There's a pretty good chance that the failure on that one, is bulging caps on the FIC motherboard, BTW. But I wouln't pay more than $600 to $700 if I were interested.
Jay

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #216 on: February 24, 2018, 03:27:51 am »
Thanks guys, what about the 500 MHz version, the 54815A?  Can the resistors be changed on the acquisition PCB to increase the bandwidth?

And what about this one as a risky purchase? https://www.ebay.com/itm/Agilent-54855A-54855-66413-DSO-Infinium-Oscilloscope-parts-or-repair-only/152916007613?hash=item239a811abd:g:~sUAAOSwATxajG-e

It's a 54855A chassis with no PC motherboard, drive, FDD, or cover.  If the acquisition PCB is good, it's 6 GHz with 20 Gsps on all 4 channels simultaneously!  If this were made good, it's asking price is $9,000 or more.

Can you guys tell from the photos whether the serious parts are there? What do you think would be involved to get it going?

[EDIT] the same seller has a 54855A power supply for sale, he wants $3,480 for it!  He doesn't realize that it's only worth $20!
https://www.ebay.com/itm/Agilent-HP-54855A-5110-PACC00-111-0950-4369-Power-Supply/152911922763?hash=item239a42c64b:g:KvEAAOSwn9VaiHG3
« Last Edit: February 24, 2018, 03:34:39 am by Gandalf_Sr »
I'd like to make the world a better place but they won't give me the source code
 

Offline nctnico

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #217 on: February 24, 2018, 08:47:27 am »
And what about this one as a risky purchase? https://www.ebay.com/itm/Agilent-54855A-54855-66413-DSO-Infinium-Oscilloscope-parts-or-repair-only/152916007613?hash=item239a811abd:g:~sUAAOSwATxajG-e
Don't touch that. At least the acquisition interface board is missing. And you might need specific videocards as well.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline Tony_G

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #218 on: February 24, 2018, 09:13:26 am »
And what about this one as a risky purchase? https://www.ebay.com/itm/Agilent-54855A-54855-66413-DSO-Infinium-Oscilloscope-parts-or-repair-only/152916007613?hash=item239a811abd:g:~sUAAOSwATxajG-e
Don't touch that. At least the acquisition interface board is missing. And you might need specific videocards as well.

Holy crap! It's missing everything including the A/D hybrids - this is worth maybe $200-300 if that - run, don't walk, run from that $1500 price. I think they even stripped some other ICs off the board. $200 might have been too generous....

TonyG

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #219 on: February 24, 2018, 11:31:03 am »

Holy crap! It's missing everything including the A/D hybrids - this is worth maybe $200-300 if that - run, don't walk, run from that $1500 price. I think they even stripped some other ICs off the board. $200 might have been too generous....

TonyG

I think the hybrids are there, but they're missing the heat sinks. But, you got to figure that they stole other parts because the ACQ board had problems...
Jay

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Offline Jwalling

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #220 on: February 24, 2018, 11:34:52 am »
Thanks guys, what about the 500 MHz version, the 54815A?  Can the resistors be changed on the acquisition PCB to increase the bandwidth?

And what about this one as a risky purchase? https://www.ebay.com/itm/Agilent-54855A-54855-66413-DSO-Infinium-Oscilloscope-parts-or-repair-only/152916007613?hash=item239a811abd:g:~sUAAOSwATxajG-e

It's a 54855A chassis with no PC motherboard, drive, FDD, or cover.  If the acquisition PCB is good, it's 6 GHz with 20 Gsps on all 4 channels simultaneously!  If this were made good, it's asking price is $9,000 or more.

Can you guys tell from the photos whether the serious parts are there? What do you think would be involved to get it going?

[EDIT] the same seller has a 54855A power supply for sale, he wants $3,480 for it!  He doesn't realize that it's only worth $20!
https://www.ebay.com/itm/Agilent-HP-54855A-5110-PACC00-111-0950-4369-Power-Supply/152911922763?hash=item239a42c64b:g:KvEAAOSwn9VaiHG3

The 54815A can be upgraded from 1GS/s to a 2GS/s 54825A.

Where can you get a a 54855A power supply for $20??
Jay

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #221 on: February 24, 2018, 12:23:49 pm »
Hello dear members, I currently have an issue with the GAL16vd8 chip on the scope. Next to the BIOS and RTC. Its fried and I cannot retrieve any info. Nor would the scope boot. Does anybody have the option to get the code from this chip labeled 1996 ami 73xx PODxxx and email it to me. thanks for your reply,
If you need pictures or else, please let me know, Best regards,
Nicolas

I may be able to help if it's not protected, and my programmer supports the device (I think it does). I'll follow up tomorrow...
In the meantime, please post the VIN # from the rear of the scope.

Not sure if this is the correct one, but here's one from the Atlas 757 board. The security fuse was not blown.
Jay

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #222 on: February 24, 2018, 03:17:24 pm »
...The 54815A can be upgraded from 1GS/s to a 2GS/s 54825A.

...Where can you get a a 54855A power supply for $20??
Thanks, what's involved in that upgrade? There are several 54815As going for reasonable money on eBay.

I thought it was just a computer power supply.  If you need one, I know where the's one going for $3,480 ;)

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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #223 on: February 24, 2018, 03:37:11 pm »
...The 54815A can be upgraded from 1GS/s to a 2GS/s 54825A.

...Where can you get a a 54855A power supply for $20??
Thanks, what's involved in that upgrade? There are several 54815As going for reasonable money on eBay.

I thought it was just a computer power supply.  If you need one, I know where the's one going for $3,480 ;)

Simple. Just add one resistor. This is from an old Yahoo HP/Agilent groups post I made some years ago:
Quote
I've spent some time comparing the 54815A scope to a 54825A scope and figured out how to make the 54810A and 54815A scopes run at 2GSa/s which make them the equivalent of a 54820A and 54825A scopes. In fact, once the change is done it will identify itself as such. Before doing this, make sure your scope will pass it's built in calibration routines from the utility menu. You'll have to run them again after the "upgrade"
On the Acquisition board there is a 50MHz DIP 4 pin oscillator in a DIP14 package. Right next to it you'll find a resistor (R134) that is not populated. on the 54820A and 54825A it is populated with a zero Ohm resistor. Add the part or just short it out with a solder blob then power it up. The scope will boot and say it needs calibration; run the cal routines and you'll be good to go. Have fun!

I just took a picture of a scrap board I have lying aroung and highlighted the resistor.

EDIT: Also, that's not an off the shelf power supply. It's custom made For Agilent. You could easily sell one for $1K in working condition.

« Last Edit: February 24, 2018, 04:23:32 pm by Jwalling »
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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #224 on: February 24, 2018, 04:21:52 pm »
Thanks, I've been looking at this one on eBay but when I zoom in on (open in a new tab) the picture, I can see a 'rejected' sticker at the top and a red 'X' alongside input number 2 - I assume a bad input channel is something that's hard to fix?
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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #225 on: February 24, 2018, 05:29:43 pm »
Thanks, I've been looking at this one on eBay but when I zoom in on (open in a new tab) the picture, I can see a 'rejected' sticker at the top and a red 'X' alongside input number 2 - I assume a bad input channel is something that's hard to fix?

Probably a bad attenuator or A/D converter. Easy to fix if you have the part(s) as they are easily removed. A/D converter is socketed, and the attenuator is held in by a screw or two. It says "see attached tag" Ask the seller if the tag is still on it, and what it says if it is.

EDIT: The attenuators were VERY problematic on those... Suitable donors can also be found in the 54540A 54542A and the 2CH variants.
The bid on that unit is from Watronics https://www.ebay.com/usr/watronics  He used to work for HP. I had an email conversation with awhile back about why they had so many problems. Apparently HP/Agilent knew about it, but were never able to figure what the exact problem/cure was. I think that the problem was the leaf contacts on the shuttle relays were making poor contact with the gold plated posts.

« Last Edit: February 24, 2018, 05:36:47 pm by Jwalling »
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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #226 on: February 24, 2018, 09:13:20 pm »
Thanks, it went for $212 plus shipping but I missed it, a reasonable price I think.  I'll keep looking.
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Re: Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
« Reply #227 on: October 01, 2018, 01:44:02 pm »
I've got an older HP branded 54845A which was failing several tests and all calibrations. I have fixed everything up. Replaced the hard drive with a compact flash, fresh install of win98 and the software with all the upgrades up to V4.5 and added memory (64MB now from 16MB before). Cleaned up the ADC ASICs etc... and now the scope passes all self tests (multiple times), passed all calibrations and everything is honky dory except a peculiar issue that was also there in the beginning when I got the scope (it used to be win95 and SW V3.72)
As you can see in the pictures, when the graphic display is enabled, all is fine and the scope works perfectly. As soon as I disable the graphic display (top right corner) the waveform is segmented as you can see. The issue is very visible on fast time bases but it also exists on slow time bases specially with low frequency square wave it is very visible and distorted
For the life of me I cannot figure out what can be wrong with it. I don't think it is the acquisition board. When I got the scope I thought it was a software/driver issue so I replaced the clunky noisy hard drive and upgraded the software but the problem persists. The only hardware issue I can think of is the display board on the PCI slot but what is in there to test?