Author Topic: Agilent 53132A Counter Repair (FIXED and Upgraded) (Read 45793 times)

HighVoltage · « **on:** January 12, 2016, 09:13:20 pm »

This 53132A counter was suppose to work well, as described by the seller but it is dead.
Symptoms: No display on, No fan, no reaction at all.
Both fuses seem to be ok.

I already got arrangements with the seller to keep it and now I have another repair job.
This thread is started at the beginning of the repair and at this stage I have no idea what the problem is.

After opening the instrument I found the fan totally plugged up with dirt and lots of dirt blown in
to the power supply area. So first I will clean the inside completely and then start analyzing the problem.
Judging by the dirty PSU, I suspect the first problem there.

After I repair the unit, I want to upgrade the the option 10/12 for a stable frequency reference and
also upgrade to to the 3 GHz Prescaler on Channel 3.

At the end there will be a calibration and comparison to my HP GPSDO with my 53230A counter.

So, anyone here having experience with the 53132A and it's problems?
One thing that sticks out right away is a missing U24 chip.
Hmmm, may be it is required for the time base upgrade?

Interestingly, this one has the Channel 1 and Channel 2 inputs on the back as well.
I think this was an option, because I have seen other units without these connectors on the back.

TheSteve · « **Reply #1 on:** January 12, 2016, 09:34:07 pm »

Wow, that is some nasty crud. I don't think U24 was ever used. The high stability option just plugs in, no changes to the main board. Same with the 030 option. I added one of the 030 ebay specials to my 53132A as well.
Being the fan should always run and the power is handled by a soft switch, the power supply really screams to be looked at first.

btw, the rear connections are option 060, they are simply in parallel with inputs 1&2, no switching or anything.

HighVoltage · « **Reply #2 on:** January 12, 2016, 10:05:03 pm »

Thanks for the feedback TheSteve,

I found the two options to be available on ebay Poland and they seem to be at an ok price level:
- 3GHz Prescaler = $89
- Ultra High stability Timebase = $ 105

Full schematics are also available here:
http://www.ko4bb.com/manuals/index.php?dir=HP_Agilent/HP_53131A_53132A_53181A_Universal_Counter

TheSteve · « **Reply #3 on:** January 12, 2016, 10:37:27 pm »

I believe there have been several different aftermarket high stability time bases made. I've seen one that is adjusted using a trimmer, and another that uses an A/D and is calibrated electronically like the factory option.
When ordering verify it is a proper clone that uses the A/D.

ManateeMafia · « **Reply #4 on:** January 13, 2016, 04:05:19 am »

I just received my option 030 from Poland. It looks good but the IC closest to the center of the board has pin 3 clipped off. Would anyone with a recent version confirm this is the case?

I contacted the eBay seller and hope to hear back soon.

ManateeMafia · « **Reply #5 on:** January 13, 2016, 04:39:58 am »

That is for the OCXO option. I did buy a blank board from Gerry Sweeney and it has worked well.

The 030 is for the 3GHz input divider. It is strange that the eBay listing shows all pins connected so I won't be surprised that this was a mistake. I will have to find the schematic for it and compare it to this board.

ManateeMafia · « **Reply #6 on:** January 13, 2016, 05:30:52 am »

Just heard from the seller that the pin was intentionally clipped.

Jf2014 · « **Reply #7 on:** January 13, 2016, 08:45:28 am »

PSU problem ?

Maybe you need a diagram PSU.

HighVoltage · « **Reply #8 on:** January 13, 2016, 10:03:49 am »

Quote from: Jf2014 on January 13, 2016, 08:45:28 am

PSU problem ?

Maybe you need a diagram PSU.

WOW!
I was looking for the PSU schematics and it was not part of the standard schematics and I could not find it.
It seems you made it?
Impressive, Thanks so much.

Orange · « **Reply #9 on:** January 14, 2016, 01:27:11 pm »

The issue with the 53132 counter series is that the are constantly powered, and the fan is blowing. This is a very disturbing noise. I have my counters disconnected from the mains if not in use.
If you get an oven controlled time-base in this thing, you will have the PSU running all the time, which will begin to irritate you (at least I had this).

Better solution is to use the external reference input and uses a GPSDO or rubidium source. It is much more accurate, and you don't need to power the counter all the time.

BTW, I noticed from the pictures that the main board in the counter has only one flash ROM for the firmware. The older type main boards have 4 separate EPROMS, which can be upgraded easy. Perhaps Agilent has a new FW upgrade possibility for this type of motherboard.

Anyhow it is a great counter

TheSteve · « **Reply #10 on:** January 14, 2016, 06:18:19 pm »

The counter does look to have newer firmware then I have seen posted anywhere - 4806. Not quite as easy to dump and post as it was with older units that had four socketed PLCC devices.

Vgkid · « **Reply #11 on:** January 15, 2016, 01:21:55 am »

Could you either substitute a different fan to run off of another rail(non standby rail).
Or, use a relay to turn on the fan(off the 5v rail, or others) and keep it wired the same way.
The 2nd one is how that is implemented in the 5335.

HighVoltage · « **Reply #12 on:** January 15, 2016, 01:11:31 pm »

Interesting comments everyone - thank you, I will look in to the fan issue, when I put it back together.
I probably have to get a new fan anyways.

Right now is cleanup time.
I took the instrument completely apart now and started with the display and front cover.
All cleaned up now, looks like new - kind of.

Next is to clean the PCB in alcohol.

EPTech · « **Reply #13 on:** January 15, 2016, 01:36:58 pm »

Hi there,

If the fan has died somewhere along the way, you should check the condition of the input cap but most certainly the low ESR output caps on the SMPS. I would just replace them by default, that may already fix the problem. I am not affiliated to any brand but I would recommend the FC, FM or FK series from Panasonic. Also check the high ohm resistors.

Does the supply work without load attached?

HighVoltage · « **Reply #14 on:** January 15, 2016, 01:53:23 pm »

Quote from: EPTech on January 15, 2016, 01:36:58 pm

Hi there,

If the fan has died somewhere along the way, you should check the condition of the input cap but most certainly the low ESR output caps on the SMPS. I would just replace them by default, that may already fix the problem. I am not affiliated to any brand but I would recommend the FC, FM or FK series from Panasonic. Also check the high ohm resistors.

Does the supply work without load attached?

Thanks EPTech
The PSU is sitting in alcohol right now since it was so full of dirt, some components were not visible.
I wanted to clean it, before I would test without load.

The corrosion on the frame is removed with a rotating steel brush but it was already deep in to the metal, even after cleaning it looked horrible.

So, I decided to cover this area of the frame with some paint.
And it seems to turned out alright.

HighVoltage · « **Reply #15 on:** January 15, 2016, 02:05:41 pm »

OK, the PCB is cleaned with alcohol and stayed in an oven for 1 hour at 50°C to get the rest of the alcohol evaporated.

EPTech · « **Reply #16 on:** January 15, 2016, 02:07:32 pm »

Really that corroded!

Makes you wonder from what environment it came out of.

I do not want to discourage you but there may be more going on than some bad caps.

Be sure to post the pics after that clean-up.

HighVoltage · « **Reply #17 on:** January 15, 2016, 02:12:18 pm »

Yes, it must have been awful in that environment for this unit.
I am actually surprised how some people treat expensive test equipment badly.
This was not the first instrument I bought used that was full of sticky and corrosive dirt.

All the sticky stuff is removed from the PCB and it looks really good now.
Here are some more PCB detail pictures.

HighVoltage · « **Reply #18 on:** January 15, 2016, 03:37:30 pm »

PSU is cleaned up with alcohol and was also one hour in the oven at 50°C
From the first look the caps seem alright (not domed out).
Time to take some measurements.

HighVoltage · « **Reply #19 on:** January 15, 2016, 04:41:03 pm »

Voltage output was all zero on all wires at the output connector.
So, I started probing at the input of the PSU.

The fix was so easy....
Probing the voltages right after the input rectifier revealed open R2.
R2 is a 15K Ohm 5 Watt power resistor.

Replacing it gave about 101V across the resistor.
That is just 0.66 Watt power and far lower than the 5 Watt rated power of the resistor.
It probably died from too much heat because of all the dirt in the PSU.

I will check the caps anyways of ESR, but I don't think they are bad.
They are all Nichicon 105 degree rated caps.
Actually looking closer at the PSU, it seems to be good quality built.

Now, without connecting the PSU to the Agilent PCB, I am getting these output voltages:

+ 5V = 5.19V
+ 12V = 12.08 V
-12 V = -11.88 V
- 9 V = -9.16 V (with separate 9V ground)

Next:
Install the PSU in to the 53132A without fan, since I don't have a fitting new one.

HighVoltage · « **Reply #20 on:** January 15, 2016, 05:36:19 pm »

Counter is fixed and working perfectly so far, tested frequency on Chanel 1 and 2.

Now I will be waiting for the parts to arrive for upgrading to 3 GHz prescaler and oven controlled oscillator.
After that I will calibrate it, based on my HP GPSDO
Parts are ordered ... stay tuned.

Thank you all for help and suggestions.

EPTech · « **Reply #21 on:** January 15, 2016, 05:40:01 pm »

Right on!

Another fine instrument added to the bench. Considering all the work you have put into it, it is probably in better shape than many 2nd handers out there.

Congrats

HighVoltage · « **Reply #22 on:** January 15, 2016, 06:07:27 pm »

Thanks.
Self Test and extended Self Test is passed without any problems.
All seems just perfect so far.

I found a fitting fan with low noise.

Sharkoon System Fan
- 7 blade fan
- 40x40x20 mm
- 6200 RPM
- 11.8 m^3/h
- 26 dB(A)
- Euro 4,38

May be this one will also solve the loud fan noise that some complained about.

TheSteve · « **Reply #23 on:** January 15, 2016, 06:56:25 pm »

Nicely done! Some one must have been measuring the frequency their fish were moving at and mounted it above a bubbling aquarium.

I plan to do the hardwired switch mod as done by Gerry Sweeney on mine, I always use an external reference anyway.

HighVoltage · « **Reply #24 on:** January 16, 2016, 02:24:01 pm »

Someone asked me, what kind of alcohol I am using for cleaning the parts and PCB's.
What I found to work really good is Flux Thinner that we use for an automatic lead free soldering robot to adjust the density of the flux.
It comes in 20 l canisters and based on pure Propanol-2
Here is the label from the canister.
Somehow this works much better that the alcohol I can buy at a drug store.


EEVblog Main Site	EEVblog on Youtube	EEVblog on Twitter	EEVblog on Facebook	EEVblog on Odysee

Author Topic: Agilent 53132A Counter Repair (FIXED and Upgraded) (Read 45793 times)

Share me