Agilent/HP 54845A

[smgvbest]

I am expecting a HP 54845A off eBay tomorrow and will start checking it out soon after I receive it.
In the mean time I did some searching for information and firmware for the scope and found many of the old links in the firmware ugrade guide where broken.  I've done some searching and found them all at the following URL
ftp://ftp.keysight.com/pub/callpub3/ddt/scope/548xx/

If nothing else this has the 4.50 firmware and other files for the scope that others may find handy.

I'll post more when I can, here's the ebay add photo for it

[xrunner]

Very nice catch, I'd sure like to see follow up pics of your checkout. 

[Jwalling]

Nice find. The voice control software is there as well. I've always wanted to try that...

[smgvbest]

I'll get more pics  soon as I can.
I did receive it today and some of you may have seen it on ebay listed as having a network password that could not be removed.   short thing,  it is now removed.   So first off in anyone runs into that issue this is what I did to remove it.   

most of what you see via google talks about getting a command prompt and deleting the *.PWL files.   those files are for local login accounts not network login accounts,   you have to get into the control panel and disable it

so  first create a win98 boot disc,  mine unit has a 1.25" floppy not the LS120 drive so I downloaded bootdisk from keysight.  the only links do not work but I found them on the keysight sight

you'll want this file
ftp://ftp.keysight.com/pub/callpub3/ddt/scope/548xx/Upg_Rec/bootdisk/CD_boot.zip
unzip it and copy to your floppy and boot the scope
once at a dos prompt go to the C: drive and edit the msdos.ini file and enable the bootmenu=1  currently it is bootmenu=0  you can also change the time the menu stays on screen,  I changed mine to 30s via bootwait=30  (doing from memory so may not be the correct one there but should get you there.

once done remove the floppy and reboot
when the menu comes up, select safe mode
go into the control panel and remove all the accounts you dont' want and create one for yourself
also go into the network setup and disable network login

once done, exit and reboot
you'll get a logon screen enter the ID and password you set up
it will setup the new user and eventually you'll have a scope screen

I'll see if I can do a better guided description of that soon

i do see some problems with the FISO?? test for Ch1,  Ch2-4 test ok.
i think this is the one where cleaning the hybrid has helped so I will try that.   I'll try to get some pics of it also

[Tony_G]

I picked up one of those from a DoD auction. Did a few videos on it here:





I ended up using a parallel CD ROM drive that I got on EBay for $20 (including original packaging)

Great scope. If you're going to recovery it then start with the 3.5 (I think) Recovery image, do the 4.3 Upgrade so you get the Web Control and then move to 4.5.

TonyG

[smgvbest]

Hi Tony,

Yep,  I've watched both your videos and Shahriar's on the scope.   thank you both for posting.
I have found it is at 4.5 already so no need to upgrade it unless I can't recover the admin password.

I just spent time more or less optimizing it.   removing old files left behind (mostly screen captures) but I can not remove norton antivirus from it so far.  it wants the network admin password which I've yet to recover.

[Tony_G]

Glad you found them useful.

Just as an FYI on this - HP released the 4.5 update as a partial (I'm guessing people complained about there being a web server on the scope) - If the previous owner went straight to 4.5 from 3.5/3.72 then you won't have that functionality.

Now is it worth it? Well I don't really think so because it requires that you run Java on your machine and that is a steaming pile of security issues wrapped up in a release number.

Good luck with the scope - Look forward to hearing how it turns out.

TonyG

[Samogon]

I picked up one of those from a DoD auction. Did a few videos on it here:

Hi,
I have same calibration problem with channel vertical calibration, and i swapped hybrids.
But it did not go away. So i assume it is in attenuator. I has been driven away with other projects. So your thread resurrected my intent to repair it.

Thanks

[Tony_G]

It sounds like you have the same issue I did - The 54845A fails calibration on channels 1 & 3 (or 2 & 4) and the troubleshooting guide says to swap the hybrids - I tried that and it didn't work but cleaning the contacts did.

Hopefully that helps.

TonyG

[smgvbest]

I just swapped the CH1 & 3 hybrids as well as cleaned them all and same results.

ADC test after I swaped CH1&3,  same result

Code: [Select]

**Test Run** : A to D Converter Test  --- 11 MAR 2017 15:42:38
Self Test invoked cal executed.
Error in self test invoked cal - DLL cal.
Error in self test invoked cal - Clk 100Mhz cal.
Error in self test invoked cal - Data Acq cal.
Error in self test invoked cal - Fiso Redundancy cal.
 Test FAILED on channel 1
Fiso's stacked, Hybrid bit is stuck.
000000000000B 000000000000B 000000000000B 000000000000B
000000000000B 000000000000B 000000000000B 000000000000B
Test A to D Converter FAILED.
**Test Run** : A to D Converter Test  --- 11 MAR 2017 15:42:50
Self Test invoked cal executed.
Error in self test invoked cal - DLL cal.
Error in self test invoked cal - Clk 100Mhz cal.
Error in self test invoked cal - Data Acq cal.
Error in self test invoked cal - Fiso Redundancy cal.
Test A to D Converter PASSED.
**Test Run** : A to D Converter Test  --- 11 MAR 2017 15:42:59
Self Test invoked cal executed.
Error in self test invoked cal - DLL cal.
Error in self test invoked cal - Clk 100Mhz cal.
Error in self test invoked cal - Data Acq cal.
Error in self test invoked cal - Fiso Redundancy cal.
Test A to D Converter PASSED.
**Test Run** : A to D Converter Test  --- 11 MAR 2017 15:43:13
Self Test invoked cal executed.
Error in self test invoked cal - DLL cal.
Error in self test invoked cal - Clk 100Mhz cal.
Error in self test invoked cal - Data Acq cal.
Error in self test invoked cal - Fiso Redundancy cal.
Test A to D Converter PASSED.

FISO

Code: [Select]

**Test Run** : FISO Test  --- 11 MAR 2017 15:43:31
Self Test invoked cal executed.
Error in self test invoked cal - DLL cal.
Error in self test invoked cal - Clk 100Mhz cal.
Error in self test invoked cal - Data Acq cal.
Error in self test invoked cal - Fiso Redundancy cal.
FISO test failed on channel 2
FISO data bit error not correctable.
Test FISO FAILED.
So basically  CH1 ADC Fail and CH2 FISO fail I get in the self test.
swapping CH1&3 did not effect the ADC Failure. 
swapping CH2&4 did not effect the FISO Failure

tried to attach some photo's but they are too big,  will uploaded to my server and link to them instead

[Tony_G]

Just for clarity, you swapped the a\d hybrids but the errors stayed on the same channel?

TonyG

[smgvbest]

That is correct
I have also checked the power supply voltages and all are in spec
I did also have it run a CAL and had the following
CH   Vertical   Trigger
1      FAIL        PASS
2      FAIL        FAIL
3      PASS      PASS
4      PASS      PASS
the Common and Ext Trigger also pass

more pics

[Samogon]

Looks like my case. I bet it is attenuator.
I dis test with good known signal and one channel, which is failing calibration showed 5% Vpp less then others. So i was hoping to buy this module off ebay, but people want more than i paid for whole unit.
So i am going to open it and debug it.

[smgvbest]

Looks like my case. I bet it is attenuator.
I dis test with good known signal and one channel, which is failing calibration showed 5% Vpp less then others. So i was hoping to buy this module off ebay, but people want more than i paid for whole unit.
So i am going to open it and debug it.

I was wondering if it might be related to the attenuator.  I am thinking about swaping the attenuators to see what happens.
on the other side though the FISO message is about a stuck bit and I wouldn't think that would be attenuator related though I could be wrong

few MB pics





and Selftest

[Samogon]

Yes it may not be the case
Here is guy nicely described his successful fix.
http://www.dasarodesigns.com/projects/fixing-an-hp-agilent-54845a-infinium-oscilloscope/

[Samogon]

Here is quote from his site

Photo of the acquisition system components. Note that each attenuator / preamp assembly handles two of the four channels. This is so that two of the ADCs can be interleaved to achieve the highest 8Gs/s sampling rate.

Understanding this, it was pretty obvious what the next test should be: to see if the problem was due to the attenuator / preamp assemblies or the acquisition hybrids, I disconnected the semi-rigied coax connecting them and injected a small signal directly into each of the acquisition hybrids. Under this condition, I got a nice clean trace on each channel, proving that the acquisition hybrids are still good. Furthermore, when I re-ran the self-test with the attenuator assembles disconnected, the A to D converter and FISO tests passed! Measuring the voltage on the output from the attenuator / preamp assembles, I see about 1.7V DC, which is consistent with the symptoms. With some more careful examination I was able to identify the trigger signal out pin on the attenuator module and when I injected into this, the trace could be triggered!

[smgvbest]

Here is quote from his site

Photo of the acquisition system components. Note that each attenuator / preamp assembly handles two of the four channels. This is so that two of the ADCs can be interleaved to achieve the highest 8Gs/s sampling rate.

Understanding this, it was pretty obvious what the next test should be: to see if the problem was due to the attenuator / preamp assemblies or the acquisition hybrids, I disconnected the semi-rigied coax connecting them and injected a small signal directly into each of the acquisition hybrids. Under this condition, I got a nice clean trace on each channel, proving that the acquisition hybrids are still good. Furthermore, when I re-ran the self-test with the attenuator assembles disconnected, the A to D converter and FISO tests passed! Measuring the voltage on the output from the attenuator / preamp assembles, I see about 1.7V DC, which is consistent with the symptoms. With some more careful examination I was able to identify the trigger signal out pin on the attenuator module and when I injected into this, the trace could be triggered!

yep,  I read that and tried to disconnect my attenuators.  re-ran the self test and had same fail on A/D and FISO
I also should add with the exception of ch 2 (which fails both verticel and trigger cal) all channels seem to work well.  I put a 120Mhz 1vpp signal on each channel and was able to get a stable signal on all but ch2 which is stuck high like in the posting you quoted so that could be that problem.
Ch1 doesn't seem to have any issues in actually displaying a signal yet fails the verticle cal.   I also put in a 1.5Ghz signal from a still under repair fluke 6082 and aside from jitter (expected, problem with the fluke) channels 1,3 & 4 read it fine.

here's CH1&3 showing the 120Mhz 1Vpp signal


and slightly different view showing CH1&4


adding more pics,  from selftest

[Samogon]

Eah it is plausible thought that attenuator/amplifier is bad. Same as mine.

[smgvbest]

Eah it is plausible thought that attenuator/amplifier is bad. Same as mine.

I will definitely swap them and see if the issue moves to channels 2&4

Does anyone have the Service Utility on 3.5" floppy or a file I can download?

[smgvbest]

So I've swapped CH1&3 on the hybrids and Ch2&4 for the hybrids and the issue remained with CH1/CH2
And now I've swapped the attenuators and the problem stayed with the channel,  ie CH1/CH2.  it did not move with the attenuator.
So the issue it CH1/2 (ADC/FISO) and it's not the hybrids or the attenuators.  hummm

I did get more pics of the board under the attenuators and the back side which I will post also.

[Tony_G]

Silly question but did you try cleaning the sockets and making sure that all of the little pogo pins are moving freely?

TonyG

[smgvbest]

Silly question but did you try cleaning the sockets and making sure that all of the little pogo pins are moving freely?

TonyG

Not a silly question but yes I did clean them but I did not check that all the pins moved freely.
worth a try so I'll do that.

[Tony_G]

Good luck - Hope it's just a simple pin issue.

BTW When you say you swapped attenuators/front-ends, did you completely re-cable them so that 1 & 2 fed into A/D Hybrids 3 & 4? or just swap 1 & 2 around?

You might be able to get away with a test using some pig tail leads instead of hard line.

The reason I'm asking is that the problem may still be in the attenuator but just impacting both channels - When the manual said "swap test" what I took that to be (and I could easily be wrong) was to take a known good attenuator/hybrid and swap it into the channel to ensure that you have isolated the issue.

I'm sure you did that and I'm just showing a reading comprehension problem.

TonyG

[james_s]

Wow that's a serious oscillator in that thing. Looks like a very nicely designed machine.

Depending on what version of Windows it runs, there are tools that can reset or recover the password. It's been a while since I've used them but I've gotten into a few old PCs before that I didn't have the password for.

[smgvbest]

Good luck - Hope it's just a simple pin issue.

BTW When you say you swapped attenuators/front-ends, did you completely re-cable them so that 1 & 2 fed into A/D Hybrids 3 & 4? or just swap 1 & 2 around?

You might be able to get away with a test using some pig tail leads instead of hard line.

The reason I'm asking is that the problem may still be in the attenuator but just impacting both channels - When the manual said "swap test" what I took that to be (and I could easily be wrong) was to take a known good attenuator/hybrid and swap it into the channel to ensure that you have isolated the issue.

I'm sure you did that and I'm just showing a reading comprehension problem.

TonyG

I physically swapped the attenuators so the Ch1/2 moved to CH3/4 and visa-vera.   with Channels 3/4 passing all test and calibrating I am taking that as that attenuator is a good unit as are the hybrids.     when I swapped them CH1/2 and CH3/4 again calibrated and passed all tests on CH3/4
CH2 completely fails.  CH1 fails on the vertical only

I don't have enough of the shorter sma cables to do all 4 channels but could maybe do one at at a time