Products > Test Equipment
Agilent 54835A scope (4 channel 1GHz / 4Gs/s) repair & uphack
Jwalling:
--- Quote from: Gandalf_Sr 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
--- End quote ---
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:
--- Quote from: Jwalling on February 23, 2018, 05:01:47 pm ---
--- Quote from: osiris2099 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
--- End quote ---
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.
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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:
--- Quote from: Jwalling on February 24, 2018, 11:34:52 am ---...The 54815A can be upgraded from 1GS/s to a 2GS/s 54825A.
...Where can you get a a 54855A power supply for $20??
--- End quote ---
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:
--- Quote from: Gandalf_Sr on February 24, 2018, 03:17:24 pm ---
--- Quote from: Jwalling on February 24, 2018, 11:34:52 am ---...The 54815A can be upgraded from 1GS/s to a 2GS/s 54825A.
...Where can you get a a 54855A power supply for $20??
--- End quote ---
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 ;)
--- End quote ---
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!
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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?
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