Agilent 53132A Counter Repair (FIXED and Upgraded)

[HighVoltage]

The entire time I just kept hearing Shahriar in my head saying "Follow the signal path" lol.

Yes, I know what you mean, I learned so much from Shahriar' repair videos, he really is a master at this. 

btw, the previous person that did the rework has some skill but not really enough to do a proper job. The soldering they did is far from excellent and they removed a part or two that there was clearly no need to remove as they can easily be verified 100% good in circuit. They also left the signature amateur calling card in the top of one of the relays in the form of soldering iron melt marks.

If that previous person did not have the skills and / or tools to do the job right, he may even have damaged some of the new components he installed. May be it is a good idea to check them all or replace them properly.

[TheSteve]

Cleaned up all of the soldering, its starting to look pretty good inside. I do need to order a replacement U44 next week. I've bypassed the chip and while it fails the self tests still it can count on both channels. If I give it the proper level input though on ch1 while booting it passes all self tests - so I'm hopeful a new U44 fixes it. I forgot to mention the other "surprise" I got the with unit. I am sure they just threw a power supply into the main board and then tossed a case on it. On the bottom of the case where it is riveted together you can see a hint of something black on the outside, on the inside it is a different story. It did not come off the 53132A PCB though as its very clean. I assume something leaked from a different board, sure is disgusting looking.

[TheSteve]

Well I fired up the bread board and tested U44 - it looks and works exactly as an op-amp should so its fine. Back to the drawing board on this one...

[edpalmer42]

Cleaned up all of the soldering, its starting to look pretty good inside. I do need to order a replacement U44 next week. I've bypassed the chip and while it fails the self tests still it can count on both channels. If I give it the proper level input though on ch1 while booting it passes all self tests - so I'm hopeful a new U44 fixes it. I forgot to mention the other "surprise" I got the with unit. I am sure they just threw a power supply into the main board and then tossed a case on it. On the bottom of the case where it is riveted together you can see a hint of something black on the outside, on the inside it is a different story. It did not come off the 53132A PCB though as its very clean. I assume something leaked from a different board, sure is disgusting looking.

Is that black stuff dry like blown capacitor guts or sticky/gooey?  In some equipment HP used stick-on rubber feet as spacers to make sure that the board couldn't touch the case.  Years later, they found that the rubber feet melted and turned into goo.  If that's what you've got, it cleans up easily with IPA.

[Zucca]

well, after reading this post here my choice:

Ebmpapst 412
12Vdc
0,9W
75mA
6000rpm
10m3/h
18dB

expensive but I saved the shipping in the Digikey order...

I am pretty pleased with the result. When I fired it up the first time with the new fan installed, I thought I messed up something since I couldn't hear it. Only in a second step I looked at it and saw the fan spinning... 

Just a head's up, in my PSU the ZD601:



had one leg flapping in the breeze. Also the corresponding solder pad below it did not show any sign of proper soldering. My guess is a production issue.

[Nuno_pt]

Hi zucca,

Here the price is 11.20€ + 23% VAT + Shipping so should be around 15€ from a local dealer.

I'll look for the ZD601 zener in my 53181A.

[uncle_bob]

Hi

One of the wonderful things about the 53181 is that most people hate them. As a result they saw no use in their "first life" and sell at a discount to the 53131 (or at least they should). I have one sitting here maybe two feet from me. The factory stock fan is completely silent. Yes, it's running. Yes I do check every so often. The display is nice and bright. There's no big pile of crud inside it from the fan.

They either are a great source of parts for the 53132 or a nice little counter all on their own.

Bob

[TheSteve]

I am 99% the 53132A is repaired - or will be when a new AD7243AR 12 bit DAC arrives. The counter has one for each front end. Data goes through the CH1 DAC (U46) into the CH2 DAC(U47). I was able to see that CH2 was mostly alive so I removed both DAC's and installed the CH2 one into CH1. I still get failures at boot time of course(CH2 DAC is missing) but CH1 now counts perfectly and reports the correct input levels. Its not the cheapest part but is easy to get which is nice. I will order the DAC and a replacement fan next week and post an update once the new part is installed.

btw, based on date code the following IC's were previously replaced - U50, U51, U52, U53, U54, U55, U65 and possibly U44. The date codes on all original parts are 96/97, the replacement parts are 2011.

[uncle_bob]

btw, based on date code the following IC's were previously replaced - U50, U51, U52, U53, U54, U55, U65 and possibly U44. The date codes on all original parts are 96/97, the replacement parts are 2011.

Hi

Either somebody was very confused, or that counter took a *major* hit to it's front end back in 2011.

Bob

[TheSteve]

btw, based on date code the following IC's were previously replaced - U50, U51, U52, U53, U54, U55, U65 and possibly U44. The date codes on all original parts are 96/97, the replacement parts are 2011.

Hi

Either somebody was very confused, or that counter took a *major* hit to it's front end back in 2011.

Bob

I am quite sure it didn't take any kind of hit and I have finally found the real problem. I am thinking they just started swapping parts trying to fix it but never got to the proper part. If it had taken some kind of hit I think something closer to the input would be damaged. Will order the DAC today, should have it tomorrow.

edit - DAC on the way via overnight fedex.

[TheSteve]

I am pleased to report another 53132A is once again 100% operational.

Here is the summary of the unit:

Bought from ebay as not working/missing parts. The pics were decent in the auction, the only thing actually missing was the back plastic frame and 3 screws. Made a low best offer, went back and forth a few times and settled at $165.00.

Received it a few days later -  it was initially dead.

Discovered the hot and neutral wires were desoldered from the IEC power connector.
Looked over the supply, saw nothing wrong and decided to try soldering them back on, supply fired up just fine other then the fan which was dead.

Unit powered up with two failures - front end and measurement. Absolutely nothing could be measured initially.

Noticed lots of previous rework. U50, U51, U52, U53, U54, U55 and U56 had been replaced. U44 was possibly replaced as well.

Found a bad solder connection on the U50 +5 volt line. With this fixed the trigger lights now turned on but everything was still dead.

Removed U44 as its readings looked a little off to me. With the outputs of U44 jumpered to ground both channels would count properly with a 2 Vpp signal.
However the signal level readings were fixed at +- 5 volts on both channels.

Tested U44 out of circuit, it worked perfectly so I reinstalled it. I had the same power up errors but channel 2 seemed to actually work, it even gave the correct signal level. I assume U44 had a bad solder connection as well initially.

This lead to me to look at U39 and U40 which are the 12 bit DACs that feed voltage to U44. Upon power up a good DAC will toggle its output a few times during the self test. I was able to see U40 toggle properly but U39 was always a fixed -5 volts on its output. I removed both of them and soldered the U40 DAC in place of the U39 DAC. I didn't reinstall U40. At this point I received three errors at power on - front end, measurement and QSPI. However channel 1 now counted properly and indicated the proper signal levels. So a DAC was certainly bad.
Ordered a replacement U40 DAC and installed it. All self tests now pass and all measurements are bang on as they should be. I also installed a replacement fan.
Lastly I ordered a bumper and handle set from ebay and will be ordering a replacement rear plastic frame and the missing 3 screws from Keysight in a week or two when I finalize what parts are needed for two other ebay purchase projects.

Good times indeed, another very satisfying repair project.

Has anyone else ever seen a factory HP sticker on the front of a unit like this one? It has the standard serial # plate on the back so I am not sure what the front one indicates unless this was an HP factory asset at some point. For now I am leaving it on the unit.

[Zucca]

Well done TheSteve thanks for sharing.
Interesting that sticker on the front... never saw that before.

[HighVoltage]

Great Job and congratulations on the success.

You could order also a new front display cover, to get rid of the HP sticker and have it more modern looking with the Agilent branding.
I have never seen such sticker before.

[uncle_bob]

Has anyone else ever seen a factory HP sticker on the front of a unit like this one? It has the standard serial # plate on the back so I am not sure what the front one indicates unless this was an HP factory asset at some point. For now I am leaving it on the unit.

Hi

I suspect it lived in an HP cal center for some portion of it's life. They cycled the 53131's out of their system after they went EOL. This one may have gone to somebody else after that (and thus the odd repair). They have a lot of calibration sites around the world, so a lot of gear sitting on benches.

All of that *sounds* pretty cool. The gotcha is the name change. Most of these outfits come up with new asset tags as soon as there is a name change. Within a year or so after the change, you don't see the old tags going on gear anymore. It may have just been a "cool sticker" somebody came up with.

Bob

[TheSteve]

It does appear as it if was rack mounted most of its life - there is some thread locker in the mount holes. The sticker is the standard embossed aluminum one used by HP so I am sure it is a true HP sticker, what it means will likely always be a mystery. I could order a new front lense but I rather like original HP branded equipment.

[bingo600]

Hi,

I have replaced the noisy fan of my HP53181A with the following:  Sunon A40201V4 (Super Silence Series  )
http://www.digikey.com/product-search/en?mpart=HA40201V4-000U-999&vendor=259

The fan is very quiet by itself  (12.8dB-A), but when installed, due to airflow & high rotation speed, it is still noticeable in a quiet environment.

Michel.

Found this Fan with comparable specs on ebay.de
http://www.ebay.com/itm/HA40201V4-999-Axial-Lufter-40x40x20mm-12V-9m-h-von-Sunon-/111317257709

/Bingo

[HighVoltage]

That fan should work well. If it is still too loud, just add a series resistor in the cable. The instrument does not need much cooling, just a small constant airflow.

[Dwaine]

I just bought a HP 53132a with the second channel BNC connector smashed.   Does anyone know where I can find a replacement BNC connector?  I looked on ebay and could not find anything.

Other than that, the unit is perfectly working.  I also added the oven crystal to the unit and that is also working great.

[TheSteve]

I just bought a HP 53132a with the second channel BNC connector smashed.   Does anyone know where I can find a replacement BNC connector?  I looked on ebay and could not find anything.

Other than that, the unit is perfectly working.  I also added the oven crystal to the unit and that is also working great.

EDIT - I have found a better connector that is confirmed to work - TE Connectivity AMP Connector 5227677-1

To me it looks like an Amp 5413879-1 - or pretty close to that. You might want to consider just stealing one of the connectors from the back panel(whichever one you'll use the least).

[Dwaine]

That's a good idea to use one from the back.   I'll keep looking for a good match BNC connector.  If I find one, then I'll post the details.

Dwaine

[edpalmer42]

How mangled is the connector?  If you're careful, it's surprising how easy it is to restore a bent BNC.

Ed

[TheSteve]

This one is an even closer match - http://www.digikey.ca/product-detail/en/te-connectivity-amp-connectors/5227677-1/A32268-ND/811166

[HighVoltage]

This one is an even closer match - http://www.digikey.ca/product-detail/en/te-connectivity-amp-connectors/5227677-1/A32268-ND/811166

That one looks like it should fit well.
I ordered an original from Keysight a while back but that one was much more expensive

[Dwaine]

Thanks everyone.   I ordered the connector from digikey.   

[Dwaine]

The Digikey part number listed here is the exact fit. Replaced the BNC connected and channel 2 calibrated/passed.  Working great.

Thanks everyone for the assistance.  I appreciate it.