HP 53131A vs 53132A hardware differences

[SMB784]

Well now I'm gonna have to look into this again!  Thanks for all your great work everyone

[daddioo]

Hello everyone, about a month ago I changed my two HP 53131A to 53132A, I followed all the comments on the site and downloaded the file for the components to add and replace, I did the job accurately with hot air welding, I replaced the eprom with the 4613 firmware, both frequency meters work fine SELFTST: PASS, GPIB AT 3, there is only one problem when I turn on this message UNCALIBRATED appears, I don't know what to do.
I wonder if there is anyone who can help me.
sorry for english, i'm using google translate
Thank you

[HighVoltage]

Did you try to calibrate the instrument with an external 10 MHz signal?
After a successful calibration with adjustment it should work and the message should stay away.

[daddioo]

yes I did this calibration with 10Mhz from the gpsdo, but it is used to calibrate option 11 10Mhz high stability, nothing to do it always appears uncalibrated.

[eliocor]

http://ftb.ko4bb.com/manuals/146.241.179.38/HP_53131A_53132A_53181A_Universal_Counter_Assembly_Level_Service_Guide.pdf
http://file.yizimg.com/327204/201684-115911255.pdf

see chapter 2
Leggiti il capitolo 2 per la calibrazione dello strumento

[daddioo]

Calibration solved, luckily I had the function generator, I did step by step as the service manual said, I did the CAL: OFFS 1 and 2 (0V) then CAL: GAIN 1 and 2 (5V) and then CAL: TI QUIK ? 10Mhz square wave 1V peak peak, doing all this disappeared the writing UNCALIBRATED.
Thanks everyone for your help
Joseph

[alexvinassa]

Hi ytsejam and Hi to everyone!
looking at the photo attached to reply 14,It seems to me that you use two identical FPGA, the XC3142A 84-PLCC instead of one XC3142 (U58) and one XC3042 (U59). Does the circuit work correctly? Are the two fpga identical? Of course, with only one type of fpga is more practical. Thanks for your attention! 

[switchabl]

According to the datasheet (https://www.mouser.com/datasheet/2/903/3000-1595472.pdf), the XC3100A are pin- and bitstream compatible with the XC3000A but they can run significantly faster. So, yes, if you can't re-use the original U58 XC3042A for some reason,  you could use two XC3142A instead.

[alexvinassa]

yeah, I have come to the same conclusion as you! I will order all the components (aliexpress  and mouser), I want to try this upgrade! I'm mainly driven by recklessness, but.. you have to have fun somehow!

[nostril]

Hi all,

Write me up as one of the successful 53131A to 53132A conversions. I have what's presumably a still-to-be-located scratchy solder joint causing intermittent MEAS and INTERP failures under cold conditions. But aside from this, I now have 12 digits per second if I let things warm up, or twist the board just right. Actually the fault is getting harder to reproduce the more I prod around (Murphy!!!) I seem to have fixed the intermittent issue by blasting under some chips with isopropyl+air, out came one or two very small solder balls. Perhaps they were just large enough to cause issues. But I can no longer reproduce the MEAS and INTERP failures except shorting two of the pins near where the ball came out (data line to gnd). I had one faulty joint (pin 29 on U59) but I couldn't reproduce the bug by lifting it to GND or VCC.

I now have 12 digits per second on my "53131A".

I would like to confirm a few things to add to the public knowledge around this hack since detailed internals of genuine '32s were hard for me to find to confirm some stuff before trying this hack:

* I made all of the component replacements in the spreadsheet earlier in the thread.
* All other passive components were sourced from Mouser using exact part number matching from the CLIP for maximum authenticity
* I sourced the two ADCs from Aliexpress. Took a gamble here but I found someone had reviewed a listing from a seller as being non-fake.    Probably someone recent from this thread
* I used a 3142 and a 3042 FPGA per the 53132A CLIP, and not two of 3142. Again, sourcing-wise I took a roll of the dice here, but the same Aliexpress ADC seller had the 3142 FPGA in stock too.
* I upgraded the SRAM to the 15ns IDT part number from the CLIP. I didn't bother trying with the original slower RAM as it may only have manifested as intermittent problems due to overclock. Not worth my time. This was obtained from an eBay seller with a fairly high (at least, high for a chip reseller) seller rating.
* MC1403D reference was obtained from another eBay seller with a similar rating
* I forgot to add it to my Mouser order, and I didn't yet want to burn the original EEPROMs even though I've backed them up... you never know... So I bought 4x AM29F010B from eBay as well. Ironically one of these ended up being the only non-working chip. Go figure. I can only speculate it is more likely to get counterfeits of popular chips that can be sold at volume?
* I found there are two resistors missing from the delta/difference spreadsheet. This is a BOM change from 100R to 422R (R195 and R196). I'm not expert enough to determine if this makes any material difference.

[ZGoode]

I'm looking to do this mod to my 53131A, but it appears to be one of the later revisions with the TSSOP flash instead of the PLCC flash.  How do I upgrade the firmware?  Do I need to remove the chip from the board to do that?

[bson]

Just as a note if you're in the U.S.: Rochester Electronics sells the PLCC-28 AD7580JP in single qty for $30.28, is an authorized reseller and claims 1511 in stock.
https://www.rocelec.com/part/01t4w00000POeYHAA1-AD7580JP

They're listed on AD's site as (under NY even though they're in MA?):

Rochester Electronics, LLC
16 Malcolm Hoyt Drive
Newburyport,MA 01950
United States
1.727.873.0962 sales@rocelec.com

[ZGoode]

Just as a note if you're in the U.S.: Rochester Electronics sells the PLCC-28 AD7580JP in single qty for $30.28, is an authorized reseller and claims 1511 in stock.
https://www.rocelec.com/part/01t4w00000POeYHAA1-AD7580JP

They're listed on AD's site as (under NY even though they're in MA?):

Rochester Electronics, LLC
16 Malcolm Hoyt Drive
Newburyport,MA 01950
United States
1.727.873.0962 sales@rocelec.com

Rochester Electronics is a trustworthy source.  Unfortunately they do not do small quantity orders.  I was looking at buying from them, but they will not process orders under $250

[bson]

Rochester Electronics is a trustworthy source.  Unfortunately they do not do small quantity orders.  I was looking at buying from them, but they will not process orders under $250

Oh, I see - so that's why 9 would need to be ordered, to get over $250.  I understand.

I looked around and unfortunately don't see anything else of interest in the parts catalog.  It's all old legacy stuff... I wonder what their business is, the repair parts business can't be large enough to pay rent for their sizeable building.  (With a sign saying "Worldwide Headquarters" at the driveway!)