Author Topic: HP 5340A Frequency Counter Resurrection  (Read 3552 times)

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Offline TERRA Operative

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Re: HP 5340A Frequency Counter Resurrection
« Reply #25 on: March 27, 2019, 02:10:05 am »
So I installed the new caps and promptly smoked a wire to the 5V power transistor.

Seems I have a problem somewhere on the 5v rail... I disconnected everything on the 5V rail so far and it now is not releasing any more smoke, so at least the power supply is fine...

It seems this unit was originally an LED display version it seems (it's a bit of a mix of parts in this unit) so I need the older style transformer and a bridge rectifier for the 175V for the nixies, plus that damned box for the  'Dir. Count Amp' plus a few other bits and pieces.

Good thing is I found a parts unit for cheap(-ish) that has all the bits I need so far, it has the old style transformer with the nixie supply winding and that dir. count amp box, and also the transformer for option 001 too! :D
I went ahead and designed the power supply board with the help of psykok who sent me pictures and measurements of his board and ordered the PCB's, so all I'll need to complete the Option 001 upgrade is to get the OCXO, but they are pretty common on ebay.

Once the parts unit arrives I'll be able to at least get the nixies lit up, then I'll start tracing what is wrong on the 5v rail.



Then the next thing, and the next thing........  |O
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Online tkamiya

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Re: HP 5340A Frequency Counter Resurrection
« Reply #26 on: March 27, 2019, 03:25:23 am »
Missing feet is due to the fact most equipment of the kind was racked.  HP stuff does not have the side support.  So take off the feet, install slide type stuff on both side of the rack, put the ears on, slide it in and bolt the front.

It's the same in US, too. 
 

Offline psykok

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Re: HP 5340A Frequency Counter Resurrection
« Reply #27 on: March 27, 2019, 08:17:34 am »
hi,

just one point, do you have the transformer for the regulator board for the option 1?

Alex
 

Offline TERRA Operative

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Re: HP 5340A Frequency Counter Resurrection
« Reply #28 on: March 27, 2019, 08:23:38 am »
hi,

just one point, do you have the transformer for the regulator board for the option 1?

Alex

Good thing is I found a parts unit for cheap(-ish) that has all the bits I need so far, it has the old style transformer with the nixie supply winding and that dir. count amp box, and also the transformer for option 001 too! :D


Yep. ;)
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Offline psykok

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Re: HP 5340A Frequency Counter Resurrection
« Reply #29 on: March 27, 2019, 08:34:46 am »
ok I food so you will be able to install the option in your device  :-+

Now I'm hunting for a logic analyser to continue the debugging of my non counting device :D

 

Online beanflying

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Re: HP 5340A Frequency Counter Resurrection
« Reply #30 on: March 27, 2019, 08:35:05 am »
Bookmarking for when I start playing with my 'for parts unit' I got earlier last year (winter time job). At least the Nixie's all glow properly, slide switch moves the DP, Oscillator works but alas I think someone has blown both inputs as they are deader than dead :'(

740B is in the que for a Recap and some other bits but the lure of the Nixie made me get it too ;D
« Last Edit: March 27, 2019, 08:37:23 am by beanflying »
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Offline TERRA Operative

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Re: HP 5340A Frequency Counter Resurrection
« Reply #31 on: March 27, 2019, 08:43:07 am »
ooh, I'd love a good nixie volt meter or the like... They don't pop up so often in Japan, it's all frequency counters all the time...
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Online beanflying

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Re: HP 5340A Frequency Counter Resurrection
« Reply #32 on: March 27, 2019, 09:08:38 am »
OT but well NIXIE >:D. I do have a fully functioning 5326B with Nixies and a Voltmeter option if you come across one. I have never done a Cal on it but very accurate too.
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Offline TERRA Operative

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Re: HP 5340A Frequency Counter Resurrection
« Reply #33 on: March 27, 2019, 09:11:52 am »
OMG, so jelly.

I got the 5340, and two small frequency counters so far. The two counters work (I repaired and restored them previously), one I use and one I'll sell to fund new purchases. :)
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Online beanflying

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Re: HP 5340A Frequency Counter Resurrection
« Reply #34 on: March 27, 2019, 09:17:23 am »
I have trawled up the parts from France and the USA to add the 8th Nixie Digit to it as well. Fairly easy to do as it is all plug in parts but I haven't got around to it  :palm:
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Offline TERRA Operative

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Re: HP 5340A Frequency Counter Resurrection
« Reply #35 on: December 29, 2019, 08:49:19 am »
Alrighty, new update! :D

I managed to score myself another two of these units in parts-mule and semi-working condition.

I've installed the Option 001 transformer, and replaced the main transformer with an older style and added the missing bridge rectifier for the +170v nixie supply.
Also, I used various other bits to replace missing parts in my unit, including that small box I was missing for the Dir. Count Amp board.

The semi-working one was showing random numbers on the display, so I began swapping the logic cards from my existing unit and found that the first one I swapped (board A23, Count Register Assembly) which I suspected, is bad, but the unit sprang to life with the replacement board from my original unit.

So this 'new' unit looks like it works on the BNC input at least which is awesome as I can use it for testing boards from my non-working unit, and I might even end up with two units working at the end (Assuming the front ends in both units aren't blown out.....)

Next step is to fix this A23 board just because it's known faulty, but I'll swap parts in and out of my original unit to get the display working right and also do repairs there as needed.
Interestingly, this A23 board is 4 layer, and gold played. Not a cheap board to make I'm sure from the mid 80's, the date codes on the IC's are around 1986...



Photos as follows:

- 'New' unit
- Original unit with stuff added.
- Faulty A23 board.
Any circuit design must contain at least one part which is obsolete, two parts which are unobtainable, and three parts which are still under development.

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Offline TERRA Operative

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Re: HP 5340A Frequency Counter Resurrection
« Reply #36 on: December 29, 2019, 04:36:47 pm »
Ok, so I have narrowed down the faulty on that A23 board to 2 or 3 chips. I'll replace all 3 just to be sure I think.

Trick is finding some.... They are HP part number 1820-0986, which are a DM86L75N or DM76L75 which cross references to SN74160, all of which seem hard to come by...
Mouser do have a SMD SOIC16 version of the SN74160, but then I'd need to use a SMD to DIP adapter board for each chip, which isn't too hard (I can get them on ebay), just a little messy.

Anyone got any of these chips laying around in your spare parts you want to sell? :D


Also, I found a dry solder joint on the +15V PSU PCB, so that's been fixed too.

I think I'll be using this new chassis as my main chassis for now as it powers up and works so far. All I really need to do is transfer the Option 001 transformer and the main power filter caps across, but the caps are screw mount so easy enough to do.
Once I have this one all working, I'll continue to fix up my existing unit so I can use the good unit as a reference seeing as the first one was a bit of a junkbox assembled unit.
« Last Edit: December 29, 2019, 05:00:41 pm by TERRA Operative »
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Offline TERRA Operative

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Re: HP 5340A Frequency Counter Resurrection
« Reply #37 on: December 30, 2019, 03:04:23 pm »
Well, Akihabara saves the day yet again!

I went to a little semiconductor store on my way to work and asked the old guy if he had any 74160, and after a bit of a think, he pulled out an old box from the shelf, blew off the dust and opened it to reveal a bunch of brand new TI parts for about a dollar each. :)

I bought 5 (so I have some spare) and replaced the faulty chips tonight, and now I have a fully working card.  ;D

Next step, swap some parts from the original unit to the new unit then start running performance tests to find what the next broken thing is.  :-/O  :-BROKE
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Offline Cubdriver

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Re: HP 5340A Frequency Counter Resurrection
« Reply #38 on: December 30, 2019, 03:08:41 pm »
Sounds like you're making good progress!  Nice to hear.

-Pat
If it jams, force it.  If it breaks, you needed a new one anyway...
 

Offline psykok

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Re: HP 5340A Frequency Counter Resurrection
« Reply #39 on: March 12, 2020, 03:15:12 pm »
I still have to fixe mine and I suspecting the same board.

Unfortunately without spare part or logic analyser it's almost impossible to track the problem

 

Offline TERRA Operative

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Re: HP 5340A Frequency Counter Resurrection
« Reply #40 on: March 12, 2020, 03:21:02 pm »
I took the shotgun approach and swapped chips until it worked and replaced the last chips I swapped.
Helps having parts from 3 units though. :D


I'll get back into it sometime soon, once the Wheel Of Fortune Repair lands in the right spot for this thing to get some bench time again. :D

I'm currently designing a new motherboard for my 16 digit nixie tube Casio 161K desktop calculator. :)
Any circuit design must contain at least one part which is obsolete, two parts which are unobtainable, and three parts which are still under development.

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Offline psykok

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Re: HP 5340A Frequency Counter Resurrection
« Reply #41 on: March 12, 2020, 03:33:05 pm »
did you found exactly which chip was faulty?

 

Offline TERRA Operative

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Re: HP 5340A Frequency Counter Resurrection
« Reply #42 on: March 12, 2020, 03:34:56 pm »
I'll take a look when I get home and let you know.


[edit] Looks like it was 5, 6, and 7 on A23 that I replaced with SN74LS160AN parts from TI.
« Last Edit: March 12, 2020, 05:27:32 pm by TERRA Operative »
Any circuit design must contain at least one part which is obsolete, two parts which are unobtainable, and three parts which are still under development.

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