HPAK Frequency Counters 53132A, 53131A, 53181A

[Rubo]

Cool. I'll wait until he has some and get one from him then.
Already hav his 8GHz one in my PM6680B, so I know he does a good job.

[KungFuJosh]

Nice! I want to get that one too, but it won't work in my CNT-90XL without making mods I don't want to make. 

[Rubo]

Nice! I want to get that one too, but it won't work in my CNT-90XL without making modes I don't want to make. 

Why do you think it would not work?
AFAIK they use exactly the same prescalers for PM6680, PM6685 & PM6690 (including the rubidium models).
But I may be missing something???

[KungFuJosh]

Nice! I want to get that one too, but it won't work in my CNT-90XL without making modes I don't want to make. 

Why do you think it would not work?
AFAIK they use exactly the same prescalers for PM6680, PM6685 & PM6690 (including the rubidium models).
But I may be missing something???

The CNT-90 is compatible, the CNT-90XL is not. The XL version doesn't use prescalers; it uses (allegedly) higher-end mixers instead. For the XL model, they cut a trace to J5, and they do some other type of coding on the unit, both of which would need to be changed to work with the standard prescalers.

[Rubo]

Got it. But since it's the XL, didn't it already come with a prescaler? In their brochure the have "Frequency range: up to 27, 40, 46, or 60 GHz"

[Cyclotron]

Nice! I want to get that one too, but it won't work in my CNT-90XL without making modes I don't want to make. 

Why do you think it would not work?
AFAIK they use exactly the same prescalers for PM6680, PM6685 & PM6690 (including the rubidium models).
But I may be missing something???

The CNT-90 is compatible, the CNT-90XL is not. The XL version doesn't use prescalers; it uses (allegedly) higher-end mixers instead. For the XL model, they cut a trace to J5, and they do some other type of coding on the unit, both of which would need to be changed to work with the standard prescalers.

Thanks for that bit of knowledge. I'll watch for updates on production with COJOTECH.  I want to get a higher frequency prescaler for my recently repaired PM6690.

[KungFuJosh]

Got it. But since it's the XL, didn't it already come with a prescaler? In their brochure the have "Frequency range: up to 27, 40, 46, or 60 GHz"

It was supposed to have the 40GHz mixer module (not prescaler), but I bought it on eBay. Some summamabitch took it out of the unit. I'm hoping to find a mixer for it eventually. I don't have anything that goes above 6GHz, so any of the mixers would be fine for me.

[Rubo]

Ouch, that sucks. Good luck with finding what you're looking for.

In all the years I've kept my eye on the 'bay, I have only seen XL twice.
And have never seen any parts for it at all.

[KungFuJosh]

I couldn't resist another project, so I built my own version of the timebase from CircuitValley's open source project. It works. Though the documentation I could find was a little lacking.

For the 5V OCXO I used, J4 and J5 both get jumped, so does J1. R1 and R3 don't get populated. I installed a couple extra components that don't get used unless you want manual control, but I figured I'd throw them in there in case I get bored and want to mess with that too.

[Cyclotron]

I couldn't resist another project, so I built my own version of the timebase from CircuitValley's open source project. It works. Though the documentation I could find was a little lacking.

For the 5V OCXO I used, J4 and J5 both get jumped, so does J1. R1 and R3 don't get populated. I installed a couple extra components that don't get used unless you want manual control, but I figured I'd throw them in there in case I get bored and want to mess with that too.

I don't know why watching automatic calibration and adjustment on the scope is so fascinating. I have been known to do that a couple times just to watch.
I also wrapped the unit in a plastic barrier. That way the OCXO stays warm and the parts around it get their cool air. I don't know if it helped me feel good.

[KungFuJosh]

I don't know why watching automatic calibration and adjustment on the scope is so fascinating. I have been known to do that a couple times just to watch.

I also find it entertaining. I forgot to attach these captures from it.

[TERRA Operative]

I just rediscovered this thread after making another thread.

Basically, does anyone know how to remove the 1.5GHz lockout on these units when they have the 1.5GHz option fitted? My 53181A only counts to 1.7GHz and it's obvious it's a firmware thing.
Maybe if anyone who has a 53181A can take a dump of any config ROM, I can do the same to compare and potentially find which bit to flip?

https://www.eevblog.com/forum/testgear/hpagilent-53181a-frequency-counter-1-5ghz-option-upgrade-to-3ghz/

[Zucca]

Cross posting here a thermal PID regulation implementation:

https://www.eevblog.com/forum/buysellwanted/hp-agilent-53131-53132-53181-gpsdo-timebase/msg6144925/#msg6144925

it could help to extend the life of ours counters...

[Zucca]

Re: FAN replacement

Out of curiosity I did an experiment to see if the damn stock fan is oversized in a configuration without any internal oven.

As posted above I installed a NTC NTCASCWE3103F on the Q1 heatsink in the PSU which is the hottest guy in town.
I then wired the NTC terminals outside and started to measure the temperature in a closed case.

I chose the quietest fan 40x40x20 on Digikey in stock 2 wire, the HA40201V4-1000U-A99 4500 rpm

Here the measurement results, Tamb was about 21C.

- unit plugged to main but power off

thermal equilibrium at 2150R --> Q1 Heatsink Temp 63.83C

- unit turned on and counting a 10MHz on CH1

thermal equilibrium at 1850R --> Q1 Heatsink Temp 68.18C

Based on that I keep that small fan and my hears are thanking me so much.

[KungFuJosh]

I set the SDG2122X with synced 10MHz 1Vpp square waves using the GPSDO as an external clock ref, and checked how they looked on the scope normal and inverted.

Then I did the normal test for step 1.
Then I swapped the input cables for step 2.
Then I inverted the signal on the SDG, and swapped the input cables back to normal for step 3.
Then swapped the input cables again for step 4.

I got another 53132A in today. This one looks like it was basically never used, and still has the plastic film on the front panel.

I went through the cal process again with my SDG6000X, and my SPD3303X on the newer unit, and it all went fine.

Now the question is, does anybody know anything about calibrating or configuring Channel 3?

This is a 3GHz compatible model, but it did not come with the prescaler card. I tried the card from my other 53132A, and it works, but it's weird. It almost seems like it oscillates in there? Some random frequencies pop up on the display, and this doesn't occur with the other unit.

If you look at the version with the LED screen that came with the prescaler, it just shows --------------- when nothing is connected.

Thanks,
Josh

[Rubo]

I have a few different versions of the SM for those and in none of them do they say anything about calibrating a Channel 3.

What it does say is this (on page 4-3):

Retrofitting to Option 015 (1.5 GHz), Option 030 (3.0 GHz), Option 050 (5.0 GHz), and Option 124 (12.4 GHz) must be performed by technicians at an Agilent Technologies Service Center.

It also mentions this (on page 3-13):

When reassembling A3 (Option 015/030) Assembly, ensure that cable W1 is not placed or folded on top of the input circuits of A1 Motherboard Assembly or is tucked behind A3 as the Counter may start reading or measuring noise.

I'm attaching the latest version of the manual:  53131_32_81A Assembly Level Service Guide.pdf (2073.11 kB - downloaded 7 times.)

[KungFuJosh]

Thanks! I didn't find anything related either.

Weird tho- I think i have the same manual with the same 31 comments, but the file sizes are different. I wonder what secret info is missing. 🤔

Since cojotech doesn't seem like he's gonna sell any prescalers any time soon, I ordered another 10GHz module from China to try out. I know it will oscillate, but I wonder if I can cure it, or reduce it.

[Rubo]

Since cojotech doesn't seem like he's gonna sell any prescalers any time soon, I ordered another 10GHz module from China to try out. I know it will oscillate, but I wonder if I can cure it, or reduce it.

Let me know how that goes. I would sure like to get mine to the GHz range. It IS my most temp stable counter from the "few" that I have 

[KungFuJosh]

Since cojotech doesn't seem like he's gonna sell any prescalers any time soon, I ordered another 10GHz module from China to try out. I know it will oscillate, but I wonder if I can cure it, or reduce it.

Let me know how that goes. I would sure like to get mine to the GHz range. It IS my most temp stable counter from the "few" that I have 

I'm going to try semi-rigid cable with one of the jacks you sent me. I might also see about shielding the board better, but after the experience I just had with the "real" prescaler, I'm curious if the shitty cable is at least partly responsible for the behavior of generic prescalers.

[BillyO]

Do you guys need 10GHz?

There seems to be 3GHz prescalers (option 030 clones) all over ebay.

[TERRA Operative]

There's not much to do with the Channel 3. Basically the performance test to check it is reading the correct frequency, and an input level test to make sure it's not deaf is all there is.


Looks like you could upgrade to the last firmware too... The latest firmware I have is attached below (Including for all three related models for posterity).
You'll probably need 4x new EPROM's, unless you get lucky and have EEPROM's in there..

[KungFuJosh]

Do you guys need 10GHz?

There seems to be 3GHz prescalers (option 030 clones) all over ebay.

Yes, my SNA goes to 8.5GHz, and I want to be able to verify that output...for no important reason other than fun.

There's not much to do with the Channel 3. Basically the performance test to check it is reading the correct frequency, and an input level test to make sure it's not deaf is all there is.

I did those tests already, and it actually performed much better than the expectations set in the service manual. Stability was good at much lower levels than expected, and it was generally stable down to 10MHz, which was awesome consider the channel is only rated down to 100MHz.

Looks like you could upgrade to the last firmware too... The latest firmware I have is attached below (Including for all three related models for posterity).
You'll probably need 4x new EPROM's, unless you get lucky and have EEPROM's in there..

Thank you. I have new EEPROMs I was going to put 4613 on, but I forgot about it. Thanks for the reminder.

Damn, now that I think about it, I'll probably have to recalibrate again. Good thing that only takes two minutes.

[KungFuJosh]

Firmware upgraded, new @dimmog cyan LED screen installed, recalibrated.

...and I installed the SMA to N panel mount jack so it wouldn't look so naked while waiting for the shitty prescaler to arrive.

[Rubo]

I'm going to try semi-rigid cable with one of the jacks you sent me. I might also see about shielding the board better, but after the experience I just had with the "real" prescaler, I'm curious if the shitty cable is at least partly responsible for the behavior of generic prescalers.

It very well might be.

[Rubo]

Do you guys need 10GHz?

There seems to be 3GHz prescalers (option 030 clones) all over ebay.

I need at least 6GHz, if it's higher, I won't complain