HP5216A 12.5MHZ Counter Nixie Tubes - Page 1
Forum section: electronics / repair

author: Johnny10
author_rank: Frequent Contributor
timestamp: July 17, 2016, 03:09:23 pm
content: 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,

author: Cubdriver
author_rank: Unknown
timestamp: July 17, 2016, 06:56:26 pm
content: I'll do some digging later - I *might* have something on that. The challenge, if I do, will be finding it.-Pat

author: Johnny10
author_rank: Frequent Contributor
timestamp: July 17, 2016, 07:56:38 pm
content: 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 !!

author: Cubdriver
author_rank: Unknown
timestamp: July 17, 2016, 08:31:47 pm
content: 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

author: Andy Watson
author_rank: Super Contributor
timestamp: July 17, 2016, 08:34:25 pm
content: 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

author: Johnny10
author_rank: Frequent Contributor
timestamp: July 17, 2016, 08:44:42 pm
content: 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.

author: Cubdriver
author_rank: Unknown
timestamp: July 19, 2016, 06:28:05 am
content: 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

author: Cubdriver
author_rank: Unknown
timestamp: July 19, 2016, 06:32:02 am
content: 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

author: Johnny10
author_rank: Frequent Contributor
timestamp: July 19, 2016, 12:44:25 pm
content: 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.

author: Johnny10
author_rank: Frequent Contributor
timestamp: July 19, 2016, 12:48:27 pm
content: The interior shots.

author: Johnny10
author_rank: Frequent Contributor
timestamp: July 19, 2016, 01:29:28 pm
content: Clock

author: Towger
author_rank: Super Contributor
timestamp: July 19, 2016, 01:47:27 pm
content: Those caps on the board to the right of the clock look fairly knackered.

author: Cubdriver
author_rank: Unknown
timestamp: July 19, 2016, 05:10:51 pm
content: 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

author: Johnny10
author_rank: Frequent Contributor
timestamp: July 19, 2016, 06:15:33 pm
content: 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 8Measured voltages across the power supply caps9.75VDC 303mv AC18.12 VDC 70.2mv AC212 VDC 2.14V ACGoing 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.

author: Cubdriver
author_rank: Unknown
timestamp: July 19, 2016, 06:46:35 pm
content: 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

author: Johnny10
author_rank: Frequent Contributor
timestamp: July 19, 2016, 09:44:34 pm
content: Thanks for going above and beyond !!!

author: Cubdriver
author_rank: Unknown
timestamp: July 19, 2016, 10:02:41 pm
content: Happy to help! I have a soft spot for nixie stuff.-Pat

author: Johnny10
author_rank: Frequent Contributor
timestamp: July 20, 2016, 01:28:06 pm
content: 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.

author: bitseeker
author_rank: Super Contributor
timestamp: September 08, 2016, 01:40:31 am
content: 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.

author: Johnny10
author_rank: Frequent Contributor
timestamp: September 08, 2016, 01:15:47 pm
content: 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.

author: bitseeker
author_rank: Super Contributor
timestamp: September 08, 2016, 06:38:10 pm
content: 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.

author: Johnny10
author_rank: Frequent Contributor
timestamp: September 22, 2016, 02:50:09 pm
content: Recapped the power supply.Now have 172.3 VDC, 5.1 VDC, 5.65Clock is accurate 1Mhz2nd Pic shows 20K signal from my HP8903BNo 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

author: Johnny10
author_rank: Frequent Contributor
timestamp: September 24, 2016, 01:09:50 pm
content: 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 ?

author: Jwalling
author_rank: Unknown
timestamp: September 24, 2016, 04:41:23 pm
content: Quote from: Johnny10 on September 24, 2016, 01:09:50 pmI would recommend Sphere.Some here:http://www.electronicsurplus.com/hewlett-packard-1820-0119-transistor-transistor-logicBut that price sucks. Does that part cross-ref to a JEDEC number?

author: bitseeker
author_rank: Super Contributor
timestamp: September 24, 2016, 04:48:26 pm
content: 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 CircuitHP 1820-0119 Integrated CircuitHP 1820-0116 Integrated CircuitHP 4 232 RCA Transistorhttp://www.ebay.com/itm/322222800112So, you might contact the seller to see if more are anticipated.

author: Johnny10
author_rank: Frequent Contributor
timestamp: September 24, 2016, 05:31:26 pm
content: I will do that.Also I have a HP5340 on the way for repair.Yikes!

author: Cubdriver
author_rank: Unknown
timestamp: September 24, 2016, 10:54:07 pm
content: Quote from: Johnny10 on September 24, 2016, 05:31:26 pmAnd so it begins.....-Pat

author: bitseeker
author_rank: Super Contributor
timestamp: September 25, 2016, 01:57:00 am
content: Quote from: Cubdriver on September 24, 2016, 10:54:07 pmThat it does.

author: TheSteve
author_rank: Unknown
timestamp: September 25, 2016, 04:20:47 am
content: Quote from: Johnny10 on September 24, 2016, 05:31:26 pmSo much hardware to enjoy, what is wrong with it?

author: bitseeker
author_rank: Super Contributor
timestamp: September 25, 2016, 04:35:16 am
content: Nothing wrong here. Johnny's joining the club.

author: Cubdriver
author_rank: Unknown
timestamp: September 25, 2016, 04:50:46 am
content: Come to the orange glowie side - we have cookies!-Pat

author: Johnny10
author_rank: Frequent Contributor
timestamp: September 25, 2016, 05:09:44 pm
content: TheSteve, I don't know what problems on 5340.I do know it is from first year 1973 !I see you just bought one, we will have to compare when mine comes in next week.I see the nixie tubes just keep multiplying. Have to watch out for that !

author: TheSteve
author_rank: Unknown
timestamp: September 25, 2016, 11:44:53 pm
content: Quote from: Johnny10 on September 25, 2016, 05:09:44 pmVery nice, it is truly a first class machine. My 5340A works perfect but I am still considering a possible re-cap. I haven't looked in detail but it does smell a little of old capacitor when first turned on.

author: TheSteve
author_rank: Unknown
timestamp: September 29, 2016, 03:56:42 am
content: Replaced the 6 electrolytic power caps in my 5340A today - no more odor when it powers up. All of the original caps measure OK but they are clearly the source of the funk. Also one of them does show some signs of leakage near one of the terminals. Not enough to leave any kind of mark on the PCB.Btw the caps all screw in to place - gold plated board and stainless steel hardware to bolt the caps in. You can still get replacements that screw in that are close in value but the cost is insane. So I opted to solder in some snap caps(1/5th the price) even though it hurt to solder to the gold PCB where the screws went. It had three voltage/capacitance values originally, I replaced them all with 50 volt 4700 uF.When you do receive your 5340A I'd check the caps/power supply before connecting power.

author: Johnny10
author_rank: Frequent Contributor
timestamp: September 29, 2016, 11:48:00 am
content: My unit should be here tomorrow or Monday.Refurbished an old Heathkit Cap checker a few months ago that you couldn't stand the smell of the electrolytic capacitors.Left them outside for a week and you could pick them up and still they smelled bad.Does this unit have the same HP decoder and buffer storage IC's as the 5216A?1820-0116 and 1820-0092.Guess I am going to buy a parts unit rather than individual chips.The best I have found are between 8-15 dollars without shipping.I emailed the seller with 3 sets for $30 but those were his last ones.

author: bitseeker
author_rank: Super Contributor
timestamp: September 29, 2016, 06:56:29 pm
content: Quote from: TheSteve on September 29, 2016, 03:56:42 amSolder the cap terminals to bolts (probably cut the heads off) and then install into the PCB?

author: TheSteve
author_rank: Unknown
timestamp: September 29, 2016, 08:08:03 pm
content: Quote from: bitseeker on September 29, 2016, 06:56:29 pmToo late, they got soldered in. On the plus side I ran the counter all night without any issues, it is still happily counting a sweeping input.I had considered making a few PCB's that the snap caps would solder to that also had nuts soldered to them so they could be screwed in place. I would have also needed to make spacers so the caps were properly supported. In the end I accepted the soldering and am very happy with the results. I really want a whole stack of gear of a similar vintage now.

author: Cubdriver
author_rank: Unknown
timestamp: September 29, 2016, 09:26:15 pm
content: Quote from: TheSteve on September 29, 2016, 08:08:03 pmAnd another one bites the dust!Welcome to the club!!-Pat

author: bitseeker
author_rank: Super Contributor
timestamp: September 30, 2016, 05:25:37 pm
content: Quote from: TheSteve on September 29, 2016, 08:08:03 pmYeah, I saw that the deed had been done, but was just thinking out loud in case someone else in a similar situation came along. It might even be something I'll have to do at some point. So, thanks for the conceptual confirmation.

author: Johnny10
author_rank: Frequent Contributor
timestamp: October 01, 2016, 12:07:23 am
content: Although this thread was about the HP 5216A and it slowly started drifting towards the 5340A I will just say...Received my new 5340A Option 001 unit today and all the nixies light and the 10-250mhz is working fine but when I plug into the rightmost input I get nothing.000.0 .Will have to check that out tomorrow.I have read about the input limit and the irreversible damage it causes.Will I be lucky or not?

author: TheSteve
author_rank: Unknown
timestamp: October 01, 2016, 12:11:46 am
content: Quote from: Johnny10 on October 01, 2016, 12:07:23 amYeah, the 5340A drift is my fault - why not start a new thread for yours. There is far too little info on them on the forum right now anyway.

author: Johnny10
author_rank: Frequent Contributor
timestamp: October 01, 2016, 12:20:47 am
content: I have to say mine is a bit funky smelling also.Since this is first year or thereabouts unit 1348AI thought it might have the same display chips as the 5216A but no. And I forgot 5216A is from late 50'sDifferent IC chips.When I open it up will do some photos.And make a new post.Unless it miraculously recovers and then what would I post.

author: bitseeker
author_rank: Super Contributor
timestamp: October 04, 2016, 12:21:17 am
content: If it recovers, then give it a general teardown thread. Those are still good and folks will talk about theirs or ones they've used, etc.

author: Cubdriver
author_rank: Unknown
timestamp: October 04, 2016, 12:30:17 am
content: I have two with the same issue (a failed custom part) that I've hopefully gotten working a replacement for. I'll take photos when I dig into the repair. It's been on the back burner for a while now...-Pat

author: anachrocomputer
author_rank: Regular Contributor
timestamp: October 09, 2016, 10:31:35 pm
content: Reading this thread prompted me to dig up my HP 5216A which I bought for £10 at Hanney's electronics shop in Bath in about 1996. It worked then, but has since suffered a failure whereby one Nixie digit is stuck at '8'. Also, it no longer lights the 'gate' lamp and hence will not measure frequency (it seems OK measuring period).Photo here:https://www.flickr.com/photos/anachrocomputer/30125695561Has anyone found a source of better-scanned schematics for the 5216A?

author: Cubdriver
author_rank: Unknown
timestamp: October 09, 2016, 11:55:57 pm
content: I always try to get paper copies of the manuals when possible, but if I'm in a hurry or no paper copy is easily available, for good PDF scans Artek Manuals is hard to beat. They list a scan of the 5216A for US$12.50, and it is typically downloadable fairly quickly once purchased (I'm not certain, but I believe that they manually approve the purchases, thus the delay). A link to the download is e-mailed once things go through.-Pat

author: bitseeker
author_rank: Super Contributor
timestamp: October 11, 2016, 02:01:48 am
content: Quote from: anachrocomputer on October 09, 2016, 10:31:35 pmThat's a nice one as well, John. It's as if they're just coming out of the woodwork now.

author: Johnny10
author_rank: Frequent Contributor
timestamp: November 05, 2016, 11:50:45 am
content: Update:Received the new HP 1820-0119 IC today and couldn't wait to solder the new chip into the 5216A.I ended up buying 2 chips on eBay for 17 dollars. Yikes!They were HP stamped but not gold plated as are the rest of the chips.Now all tubes are working properly and also all Frequency and Sensitivity knob positions.Measuring 10Mhz from the back of my new ovenized 5335A shows 10.00002 / 10.00003 pretty good!

author: Johnny10
author_rank: Frequent Contributor
timestamp: November 05, 2016, 05:18:10 pm
content: AnachrocomputerI followed the 9 and 8 pin on the 1820-0119 chips. These pins connect each chip in series.When I reached the 6th chip there was wrong voltage.Checked the BCD code and chip 6 was outputting the code for "8".Did not change no matter the input.Following the pinouts through to the last driver chip all 1820-0092 they all had proper high and low signals.Only the one chip showed a problem.Of course took a few hours to decipher all the reverse signal levels through to each nixie tube.I would check that Decade counter chip for the nixie tube showing "8".Pin 9 feeds pin 8 of the following chip. This is where the error showed up on mine.I then eliminated the Buffer Storage chip and the Decoder driver.By following the BCD Code between chips using the A4 Main Board Schematic page 3 of 3.The manual also has individual pin layouts and notes on each of the chips in the driver circuit.Good Luck,

author: bitseeker
author_rank: Super Contributor
timestamp: November 06, 2016, 02:56:23 am
content: Quote from: Johnny10 on November 05, 2016, 11:50:45 amYeah, they are rather pricey. Congrats on the successful repair. She lives!

author: zike
author_rank: Contributor
timestamp: December 28, 2017, 10:10:37 pm
content: So it appears "attached" by relevance... (despite thread being dormant over a year...)I just fixed a 5216A with a peculiar, but ultimately similar, problem. At first I thought it was grossly out of cal, but the error was huge and changed depending on the sampling time/decade; whereas the well-aged internal crystal was dead nuts (<0.1 ppm error!).Turned out the 5th digit appeared superficially to increment (even carried tens to the 6th digit), *except* it skipped 2, 3, 6 and 7. Somehow that digit's 1820-0093 decade counter (predecessor of the faulty 1820-0119 above) had a stuck bit, but still worked otherwise; it just divided by 6, instead of 10!I surmised the 1820-0093 and -0119 IC pinouts were identical, based on schematic backdates. Indeed, a -0119, pulled from a later-model counter with other issues, works fine in place of the failed -0093. Which is lucky as the -0093 appears even more $$$ "unobtainium".Also worth noting, these parts (and the unusual upside-down Burroughs B-5560 Nixies) are shared with the lesser 5221A and 5321A 'economy' counter models, which are more common, and less worth fixing.Hope this info helps someone else down the line.

author: bitseeker
author_rank: Super Contributor
timestamp: January 03, 2018, 12:28:51 am
content: Thanks for the substitution info, Zike.