Author Topic: HP 53131A vs 53132A hardware differences (Read 6974 times)

james_s · « **on:** March 25, 2020, 03:04:57 am »

I noticed my 53131A actually has a 12 digit display and indeed it appears that the entire front panel board is the same as that used for the 53132A. I don't suppose it's possible to hack it to get those extra digits? The 53132A seems to use a whole different mainboard but I haven't been able to find out whether it's actually a whole different PCB or the same board with some of the missing components populated and different firmware. I assume somebody here must have compared the two? I was surprised I didn't see any discussion of this either here or elsewhere around the web. I don't really need the extra precision, I just quite like hacking gear to unlock latent capabilities.

TheSteve · « **Reply #1 on:** March 25, 2020, 03:09:06 am »

It has been discussed here before(somewhere), just add the missing parts and update the firmware and you should be good to go. I don't think anyone has ever actually done it though.

eliocor · « **Reply #2 on:** March 25, 2020, 03:59:11 am »

Several years ago I compared the two schematics: the '132A has some different values and some more ICs. It can be done except for one SMALL problem: the required ADC (AD7580JP) is UNOBTAINIUM* !
The PCB are the same, just differently populated.

*) if someone of you are able to find some AD7580JP, I would be grateful if you will sell me 1 or 2 pieces of them: all of the ones available on Chinese market are fake. Please do not ask me how I know! Maybe via some brokers, but....

coromonadalix · « **Reply #3 on:** March 25, 2020, 12:06:53 pm »

reply #12 gives some infos

https://www.eevblog.com/forum/testgear/my-ocxo-purchase/

CalMachine · « **Reply #4 on:** March 25, 2020, 04:42:51 pm »

Quote from: james_s on March 25, 2020, 03:04:57 am

I noticed my 53131A actually has a 12 digit display and indeed it appears that the entire front panel board is the same as that used for the 53132A. I don't suppose it's possible to hack it to get those extra digits? The 53132A seems to use a whole different mainboard but I haven't been able to find out whether it's actually a whole different PCB or the same board with some of the missing components populated and different firmware. I assume somebody here must have compared the two? I was surprised I didn't see any discussion of this either here or elsewhere around the web. I don't really need the extra precision, I just quite like hacking gear to unlock latent capabilities.

I believe you can get those extra 2 digits with a longer gate time. If I recall correctly, a 10 second gate time yielded the full 12 digits

DeepLink · « **Reply #5 on:** March 25, 2020, 06:33:45 pm »

It is indeed possible to get hold of these ADC's, but they are expensinv ~25$ each

Quote from: eliocor on March 25, 2020, 03:59:11 am

Several years ago I compared the two schematics: the '132A has some different values and some more ICs. It can be done except for one SMALL problem: the required ADC (AD7580JP) is UNOBTAINIUM* !
The PCB are the same, just differently populated.

*) if someone of you are able to find some AD7580JP, I would be grateful if you will sell me 1 or 2 pieces of them: all of the ones available on Chinese market are fake. Please do not ask me how I know! Maybe via some brokers, but....

eliocor · « **Reply #6 on:** March 25, 2020, 06:51:19 pm »

Quote

I believe you can get those extra 2 digits with a longer gate time. If I recall correctly, a 10 second gate time yielded the full 12 digits

No, the higher resolution is due to a different HW (more precise ADC) with the same gate time.

Quote

It is indeed possible to get hold of these ADC's, but they are expensinv ~25$ each

Can you recommend a TRUSTED seller (1-2 quantity)? I got "burned" by fake ICs too much time!
I have a 53131A which is waiting for the ADC transplant: the other components are already replaced/installed.

ch_scr · « **Reply #7 on:** March 25, 2020, 07:28:32 pm »

via Octopart: https://www.rocelec.com/part/ANAANAAD7580JPZ
They are an authorized seller: "Distributors marked (...) are members of the ECIA (Electronic Components Industry Association) or are authorized by the manufacturer to sell their products (or both)." HQ located in the US.

eliocor · « **Reply #8 on:** March 25, 2020, 08:22:18 pm »

I asked for 1-2 pieces, not MINIMUM 9!

ch_scr · « **Reply #9 on:** March 25, 2020, 08:36:24 pm »

Sorry, but i do not know another reputable source. OTOH: If you get it to work, the other 8 will sell on here for sure

SMB784 · « **Reply #10 on:** March 25, 2020, 10:05:02 pm »

Quote from: ch_scr on March 25, 2020, 08:36:24 pm

Sorry, but i do not know another reputable source. OTOH: If you get it to work, the other 8 will sell on here for sure

Uh, yeah! If someone has a definitive guide on how to upgrade the 53131 to the 53132 with all the necessary parts, I would definitely buy two from you.

CalMachine · « **Reply #11 on:** March 25, 2020, 10:30:47 pm »

Quote from: eliocor on March 25, 2020, 06:51:19 pm

Quote
I believe you can get those extra 2 digits with a longer gate time. If I recall correctly, a 10 second gate time yielded the full 12 digits

No, the higher resolution is due to a different HW (more precise ADC) with the same gate time.

I realize with the same gate time you would need the additional hardware. BUT, if you don't/can't get the additional hardware, I think increasing gate time will provide those extra digits. (Through averaging)

If you don't have a 53131A and can't provide evidence that 53131A still yields 10 digits with gate time of 10 seconds.... then go away.

james_s · « **Reply #12 on:** March 26, 2020, 12:44:50 am »

Shoot, thwarted by obsolete silicon

Well a minimum order of 9 ADCs is not a huge deal if they are actually genuine, given what a 53132A costs I would bet there are easily enough people here who would go in for a couple even at $9 each if we could determine with some certainty what is needed. This is the sort of project that would be well suited to try on a scrapper motherboard that has something else wrong with it. I haven't looked at the datasheet for that ADC yet, is there something special about it or might there be an electrically compatible part in a different package that could be adapted?

If I could get the other digits with a longer gate time that would be reasonable and at least it wouldn't bug me having those digits sitting there unused. I only got the counter recently and fixed it up, I've been using it for basic measurements but have not really delved into what all it can do yet. It's certainly a lot nicer to use than my old Protek counter, I was not even aware until recently that reciprocal counters were a thing. Had I know how much nicer these are I would have bought one years ago.

eliocor · « **Reply #13 on:** March 26, 2020, 02:12:24 am »

Being stranded at home (I live in Italy) I was not able to reach my two 53131A units and my notes regarding the differences between the two models, so I made a quick "blink comparison" on the schematic pages.
Attached you'll find the "blink" PDF (Red=53131A/Green=53132A) and an XLSX with the list of the different components.
Hope it can be useful to someone of you....
http://literature.cdn.keysight.com/litweb/pdf/5989-6307EN.pdf
http://literature.cdn.keysight.com/litweb/pdf/5989-6308EN.pdf

[Edited about one year later....]
the spreadsheet has been replaced with an updated one (added C203), due to a suggestion by ytsejam: the older one has been removed
https://docs.google.com/spreadsheets/d/e/2PACX-1vT2Cw7BYP3INiD25b4SDg2K0neCQuzmEF8RHb0b05xkjEJA0OHkFD3Vtjcn3vYeawHzW9UgewXsksDZ/pubhtml

ytsejam · « **Reply #14 on:** March 17, 2021, 06:35:55 pm »

Quote from: eliocor on March 26, 2020, 02:12:24 am

Being stranded at home (I live in Italy) I was not able to reach my two 53131A units and my notes regarding the differences between the two models, so I made a quick "blink comparison" on the schematic pages.
Attached you'll find the "blink" PDF (Red=53131A/Green=53132A) and an XLSX with the list of the different components.
Hope it can be useful to someone of you....

Thanks eliocor! The overlapped schem comparison is amazing!

I've successfully converted a 53131A to 53132A.

james_s · « **Reply #15 on:** March 17, 2021, 06:42:19 pm »

That's cool, where did you get the parts to do so? I shelved the idea after determining that at least one of the critical parts was unobtanium.

ytsejam · « **Reply #16 on:** March 17, 2021, 06:58:47 pm »

Quote from: james_s on March 17, 2021, 06:42:19 pm

That's cool, where did you get the parts to do so? I shelved the idea after determining that at least one of the critical parts was unobtanium.

I got these ICs from China. Not from ebay, from Taobao instead. There're still some decent sellers who provide these NOS parts.

james_s · « **Reply #17 on:** March 17, 2021, 09:06:07 pm »

Could you share a specific seller that had genuine parts? I might explore this project again.

eliocor · « **Reply #18 on:** March 18, 2021, 03:00:55 am »

Thanks to ytsejam I corrected the spreadsheet with the differences between 53131A and 53132A models:
you can find the new document attached to this message or you can consult it online:
https://docs.google.com/spreadsheets/d/e/2PACX-1vT2Cw7BYP3INiD25b4SDg2K0neCQuzmEF8RHb0b05xkjEJA0OHkFD3Vtjcn3vYeawHzW9UgewXsksDZ/pubhtml

ytsejam · « **Reply #19 on:** March 18, 2021, 08:10:29 am »

Quote from: james_s on March 17, 2021, 09:06:07 pm

Could you share a specific seller that had genuine parts? I might explore this project again.

PM sent

anotherlin · « **Reply #20 on:** March 19, 2021, 09:07:20 am »

Quote from: ytsejam on March 17, 2021, 06:35:55 pm

I've successfully converted a 53131A to 53132A.

Where did you find the firmware ROMs?
Also, do you know if firmwares can be upgraded for all mainboard revisions?
According to the assembly level repair manual, there has been several ones.

eliocor · « **Reply #21 on:** March 20, 2021, 02:42:57 am »

Quote

Where did you find the firmware ROMs?

go to KO4BB web site: http://www.ko4bb.com/getsimple/index.php?id=manuals and search for "53132A"

BTW: I have updated the component list inserting DigiKey codes and links

TheSteve · « **Reply #22 on:** March 20, 2021, 02:47:58 am »

There are also a couple threads posted on the forum here with firmware attached.

anotherlin · « **Reply #23 on:** March 20, 2021, 06:23:06 pm »

Hi everyone,

Thanks for your answers.
I've also checked other 53132A related topics, lots of discussions and information.
In particular, about how to switch to a less noisy fan or how to calibrate (there is even a calibration fixture in the work).
It would benefit us all if we can put all the related information on one webpage, KO4BB comes closest to that.

One more question, I've noticed that latest available firmware is "4613". That would be 2006 (HP serial number is 2 first digits + 1960).
Will that work with any hardware revision of the 53132? In particular, early ones? Mine has serial number 3546A...

Best regards,

ytsejam · « **Reply #24 on:** March 21, 2021, 05:39:08 am »

Quote from: anotherlin on March 20, 2021, 06:23:06 pm

One more question, I've noticed that latest available firmware is "4613". That would be 2006 (HP serial number is 2 first digits + 1960).
Will that work with any hardware revision of the 53132? In particular, early ones? Mine has serial number 3546A...

Best regards,

Your serial number seems to be the early version with HP in stead of Agilent on the front panel.
Based on a service note 53131-04A, S/N below 3710Axxxxx seems does not have the mother board 53131-60004.
I think mother board will be the concern instead of firmware version.

I also got an US version HP 53131A with S/N start with 3736A.
It can be upgrade from FW rev3703 to rev3944 without any problem.
Although I haven't tested yet, but I don't think it will be a problem for running rev4613.


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Author Topic: HP 53131A vs 53132A hardware differences (Read 6974 times)

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