Author Topic: HP5216A 12.5MHZ Counter Nixie Tubes (Read 12163 times)

Johnny10 · « **on:** July 17, 2016, 03:09:23 pm »

Just purchased this unit and wondering if anyone had a clearly readable schematic?
Downloaded the manual from the Keysight/Agilent site but it is unreadable.
I can make out text but not the schematic or parts list.

Thanks ahead of time,

Cubdriver · « **Reply #1 on:** July 17, 2016, 06:56:26 pm »

I'll do some digging later - I *might* have something on that. The challenge, if I do, will be finding it.

-Pat

Johnny10 · « **Reply #2 on:** July 17, 2016, 07:56:38 pm »

Thanks Cubdriver !
I played with it a while this afternoon and now the 10 meg and 1 meg nixies have stopped displaying properly.
Second digit is stuck on 8 and first digit stays at zero.
Hope I am not burning out driver chips !!

Cubdriver · « **Reply #3 on:** July 17, 2016, 08:31:47 pm »

I'm pretty sure that they're cascaded counters, so if the second from the left is somehow locked on 8, then it will never send a pulse to increment the extreme left one.

-Pat

Andy Watson · « **Reply #4 on:** July 17, 2016, 08:34:25 pm »

Hmmmmmmmm ... nixie porn!

If the digits are stuck the problem is more likely to be further down the chain than the drivers.

See if this helps:
http://cp.literature.agilent.com/litweb/pdf/05216-9006.pdf

Johnny10 · « **Reply #5 on:** July 17, 2016, 08:44:42 pm »

Yep, that's the one I downloaded. Parts list and schematics are all distorted from scan.
And I did pull that bug out of the switch !!

They are so cool to look at !

That makes sense about the tube increment.
I sent 10-12 Mhz through and no change from zero.

Cubdriver · « **Reply #6 on:** July 19, 2016, 06:28:05 am »

Ok, I found the op/service manual. Of course it has a bunch of those three foot wide fold out schematics. I'll try to do some scans tonight. My first attempt didn't go well, as of course they're juuuuuust a little wider than three pages, so when I tried a three step scan a strip was missing form the schematic. Perhaps I'll try taking a photo instead.

-Pat

Cubdriver · « **Reply #7 on:** July 19, 2016, 06:32:02 am »

Oh, and a quick check of evilbay shows a vendor selling the manual for $18.75 OBO with $4.22 shipping; you might be able to get it for $15-16 + shipping...

-Pat

Johnny10 · « **Reply #8 on:** July 19, 2016, 12:44:25 pm »

Thank you for the time you spent.
I guess I will look to buy a manual.
Have had a lot of luck with Dave at Artek.
Wasn't sure what to do with this unit but the more I watch the nixie tubes spin and glow as it searches for frequency measurements...
maybe restore this unit?

It is in awful shape inside but it does partially function. Tubes are bright and it measures accurate frequency.

I did notice looking back at the first photo I took of display that the stuck nixie worked when I first turned the unit on.

This counter and the 2 other items I bought coming from same owner were sitting in a barn untouched for 20 years.
I picked up a Heathkit IT-28 and a Heathkit IM-11 and those also had a lot of bad mildew and droppings inside.

Johnny10 · « **Reply #9 on:** July 19, 2016, 12:48:27 pm »

The interior shots.

Johnny10 · « **Reply #10 on:** July 19, 2016, 01:29:28 pm »

Clock

Towger · « **Reply #11 on:** July 19, 2016, 01:47:27 pm »

Those caps on the board to the right of the clock look fairly knackered.

Cubdriver · « **Reply #12 on:** July 19, 2016, 05:10:51 pm »

The Artek manual scans are fantastic, and I don't think you'll find better copies than those that Dave makes, but in my mind they still don't beat having the actual original HP paper manual in your hand. The schematics are much easier to read as fold outs rather than either trying to scan back and forth on the computer screen, or trying to print out and tape together hard copies. If I can't get a reasonably priced paper copy I definitely buy scans from Dave, but given the option between a PDF and original paper, IMO there's no contest. (And I have bought about a half dozen of his scans, so I know their quality.)

Perhaps I'm old fashioned, but I still prefer reading things with pages that flip to images that scroll. Especially when comparing things a few pages apart, it's far easier to me to hold the pages and flip back and forth as needed, or stick something in as a bookmark to rapidly get back.

As for your 'new' counter, I personally would definitely do my best to repair it, if for no other reason than it's a cool old piece of technology. If it's been sitting unused in a barn for 20 years, I'd start by looking at power supply ripple. HP used high quality caps, but they may be toast by now. Cleaning the crud off of it would also help to eliminate any leakage paths that might be sending signals astray.

I would be happy to scan or photograph the schematics or sections thereof for you to get you started while you wait for an actual manual copy if you'd like. The power supply isn't terribly big.

-Pat

Johnny10 · « **Reply #13 on:** July 19, 2016, 06:15:33 pm »

As I have said I do have the Agilent copy of the manual but the parts list and schematics are impossible to read.
Last night I followed the Front Panel Troubleshooting guide and it suggests looking at A4Q8.
But I don't know where it is !! A4 Main board Transistor 8

Measured voltages across the power supply caps
9.75VDC 303mv AC
18.12 VDC 70.2mv AC
212 VDC 2.14V AC

Going to have to do a bit more reading.

I do agree with you Cubdriver about paper manuals.
While working on my Sencore LC102 I had to print out 8 pages and paste them all together to make the schematic.

Cubdriver · « **Reply #14 on:** July 19, 2016, 06:46:35 pm »

Main board layout(Q8 on left side near bottom, adjacent to IC 12):

Main part of schematic - Q8 near center:

Additional image showing left edge of page:

Not perfect, but I hope this helps.

-Pat

Johnny10 · « **Reply #15 on:** July 19, 2016, 09:44:34 pm »

Thanks for going above and beyond !!!

Cubdriver · « **Reply #16 on:** July 19, 2016, 10:02:41 pm »

Happy to help! I have a soft spot for nixie stuff.

-Pat

Johnny10 · « **Reply #17 on:** July 20, 2016, 01:28:06 pm »

OK. So I ordered the paper copy of manual.
Guess I will start cleaning up unit and start looking for specs of Capacitors to change in power supply.

bitseeker · « **Reply #18 on:** September 08, 2016, 01:40:31 am »

Johnny10, how's your 5216 coming along? I've had a couple of these for a little while and Cubdriver was in the process of getting one.

Johnny10 · « **Reply #19 on:** September 08, 2016, 01:15:47 pm »

I picked up the paper manual and am now waiting for the new caps to come in.
Funny you should bring that up this morning... I was just reading the thread "Let's see your nixie equipment" and thought hey this thing has to get back on the bench!

Will keep you up to date.

I will say it was very accurate before I took it all apart.

bitseeker · « **Reply #20 on:** September 08, 2016, 06:38:10 pm »

What a coincidence. We've gone from none of this model to several in the span of a few months. Looking forward to getting them all running well again.

Johnny10 · « **Reply #21 on:** September 22, 2016, 02:50:09 pm »

Recapped the power supply.
Now have 172.3 VDC, 5.1 VDC, 5.65
Clock is accurate 1Mhz

2nd Pic shows 20K signal from my HP8903B

No luck with the driver circuit yet.
Starting to investigate stuck 6th digit today.
I get proper readings on display just not able to get proper display on 6th and 7th tubes

Johnny10 · « **Reply #22 on:** September 24, 2016, 01:09:50 pm »

Where do you buy the driver chips for this unit?
I found the 6th digit 1820-0119 chip is faulty.
It is outputting the bcd code for "8" no matter the input.
The 10x divider pin output lost output voltage also.

I see Sphere has some.
Any other recommendations ?

Jwalling · « **Reply #23 on:** September 24, 2016, 04:41:23 pm »

Quote from: Johnny10 on September 24, 2016, 01:09:50 pm

Where do you buy the driver chips for this unit?
I found the 6th digit 1820-0119 chip is faulty.
It is outputting the bcd code for "8" no matter the input.
The 10x divider pin output lost output voltage also.

I see Sphere has some.
Any other recommendations ?

I would recommend Sphere.
Some here:
http://www.electronicsurplus.com/hewlett-packard-1820-0119-transistor-transistor-logic

But that price sucks. Does that part cross-ref to a JEDEC number?

bitseeker · « **Reply #24 on:** September 24, 2016, 04:48:26 pm »

Last month, there was a listing on eBay for a digit repair kit (used parts from HP counters). I thought I saw it originally listed for one set of components, but it looks like it was revised to be three kits (three complete sets) and the price adjusted, accordingly, before it sold. The kit contained the following:

HP 1820-0092 Integrated Circuit
HP 1820-0119 Integrated Circuit
HP 1820-0116 Integrated Circuit
HP 4 232 RCA Transistor

http://www.ebay.com/itm/322222800112

So, you might contact the seller to see if more are anticipated.


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Author Topic: HP5216A 12.5MHZ Counter Nixie Tubes (Read 12163 times)

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