Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack

[Converter]

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.

[nctnico]

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.

[Converter]

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.

[nctnico]

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.

[Converter]

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).

[nctnico]

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.

[Converter]

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.

[free_electron]

machines work fine without the gpib

[nctnico]

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.

[osiris2099]

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

[Gandalf_Sr]

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?

[nctnico]

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.

[Jwalling]

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.

[Gandalf_Sr]

My low ball offer was declined, so be it.  I'm not paying $900 for an as-is broken scope + $100 shipping.

[TheSteve]

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.

[Jwalling]

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.

[Gandalf_Sr]

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

[nctnico]

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.

[Tony_G]

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

[Jwalling]

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...

[Jwalling]

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??

[Jwalling]

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.

[Gandalf_Sr]

...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

[Jwalling]

...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:

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.

[Gandalf_Sr]

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?