I'm Back: ZM1022 and B-7971

[Robert G. Schaffrath]

It has been many years since I was active in any Nixie group. I had last posted quite some time ago in the the Yahoo Groups Nixie forum.

Recently I happened to do a search for some electronic components and one of the "you might also be interested in" items was a Nixie clock kit. I was rather surprised to see how inexpensive it was (obviously sans tubes) and, upon further searching further, seeing the variety of tubes supported by different kits. Way back in 2002 when I was back looking at Nixie tubes due to the IEEE Spectrum article published back then, I purchased a lot of 25 NOS Philips ZM1022's for a relatively cheap price that I planned to use for a project. I even purchased an OZ2CPU kit and assembled it but then never got around to actually doing anything with it.

Fast forward to now and one of the items I saw was a pre-assembled ZM1020/QS30-1 clock for USD$33 that required only the power supply, tubes and CR1022 backup battery. For the price I decided to take a chance, since I have plenty of ZM1022 Nixie tubes. I have to say I was pleasantly surprised at the quality and functionality. It even has an anti-poisoning routine. I like it so much I decided to get another one.

Meanwhile I was looking to see what Nixie tubes sell for now and I am stunned at how the prices have skyrocketed. I see very few ZM102x tubes and the prices are insane. At least the Chinese QS30's are not that expensive though they still sell for more than I paid for the ZM1022's. I was also amazed to see what B-7971's are selling for now. I still have my old MM5311 based six tube clock that I built back in 1979 and have occasionally upgraded to newer components. I recently saw individual used tubes selling for ~USD$130 each. I am thinking I will need to put the box of 6 NOS Ultronics B-7971's I still have in a Safe Deposit box LOL. I've had them for almost 40 years now and paid about USD$5 each for them from either Poly Paks or Meshna Electronics (you could buy used tubes for $1 less so I decided to spend the extra $1 and buy unused). I also have one used Burroughs branded (not Ultronics) B-7971 as well that has a slightly different interior assembly compared to the Ultronics tubes. So I currently have a grand total of 13 tubes if I add in the six I am using with the old clock.

Finally, I have been thinking of replacing my now 40 year old handiwork with the OZ2CPU kit I assembled as it supports B-7971's. The design I followed uses the line frequency for time keeping. Unfortunately it tends to drift quite a bit during the day and any line noise can cause the time to change quite a bit. Also I am finding the whine from the multiplexed tubes bothers me more now than it did when I was younger. That tells me it is time to modernize.

Robert

[Jim KO5V]

Hi Robert,

HI Robert,

Which OZ2CPU clock do you have? I just built 2, V1.08 clocks (ca 2005-ish), running IN-18 tubes, and V5.8 firmware. Our mains frequency is very flaky, and I was being slowly driven nuts by the clocks sometimes gaining several seconds per day. Maybe the long-term average is fine, but I can't seem to deal with it!

The kits were designed to take a 50Hz, 60Hz or 1pps reference signal. I found the DS3231 clock chip, which is compensated for temperature, and is very accurate. It puts out a 32.768 kHz square wave, which when put through a couple of flip-flops, gives a ~5V 1pps square wave (.5 sec on, .5 sec off). The clocks have been accurate since I added this circuit.

However, there is one "glitchy" thing: it takes exactly 39 seconds from when the "set" button is pressed, for the seconds start counting. It's no problem, I just have to set it for the next minute, and press the set button at 21 seconds after the current minute starts. This delay is consistent.

I ordered a new PIC withe the latest firmware (V6.3, I think). A "slot machine" effect was added to prevent cathode poisoning (it does this every 10 minutes, which is a bit too often for me). With the new PIC, the 1pps input does not cause the 39 second delay, and it keeps perfect time, but it screws up the slot machine effect so each tube shows one number for 3 seconds when it is supposed to be doing the tube-saving routine. It works fine with the 60Hz reference.

I have gone back to the original firmware, and am just living with the 39 second set delay. I have added LDRs to the clocks, which gives them four tube illumination levels. That should help with the tube life.

I also have one of his two-tube B7971 clocks that has been running for about 15 years. Since there are no seconds, I haven't noticed any error, so no stress there!

If you would like some details as to what I did to convert the clocks to the 1pps reference, let me know. I invented nothing here, just combined the work of other folks!

Good luck.  Jim

[Jim KO5V]

Is there a way to edit a message after it is posted?

[Robert G. Schaffrath]

The OZ2CPU kit I have was purchased in late 2002. According to the paperwork I have, the firmware is 5.3. Upon closer inspection I see it only supports two B-7971's, not six.

The old MM5311 chip on my clock has its reference pin tied to line for its reference. Many moons ago I had plans to switch to an MM5369 60Hz reference that uses 3.579 MHz color burst crystals. Just to keep it old school of the era. But I find as I have gotten older I have less time for the board level hacking that I used to do and instead wind up doing more pre-built component assembly. This latest 4-digit ZM1020 clock I got would be case in point. I had to get a power supply, tubes and still need to fashion a stand for it. The limit of my "assembly" work was nothing more than I would do to assemble a PC these days. I have to say the accuracy of this ZM1020 clock is incredible. Over a week running now and it is still accurate to the second. No idea what they are using for the time base and I really wish I had a schematic for it.

[Robert G. Schaffrath]

Shortly after I wrote my previous post, I came across yet another ad for one of these 4-Bit QS30 clock modules and it says it uses a DS3231 clock chip. So that explains the accuracy. The ad also has a link to a PDF instruction sheet (in Chinese).

I am amazed there is enough of a market for these clocks that a Chinese firm went and designed several different modules. The QS30 module is a variant of an IN-12 module also sold. I've never been a fan of the IN-12's with their inverted "2" to create a "5". I would hunt down genuine Burroughs or National tubes instead (which would cost me dearly I am sure).

On Friday, October 4, 2019 at 12:01:37 PM UTC-4, Jim KO5V wrote:

[Jim KO5V]

My two-tube clock is a V5.3 as well, and has been running for just over 15 years. It uses 120VAC, with no external transformer, so I guess that's now considered "dangerous". However, I'm still alive.

The inverted 2 has always bothered me as well, and a lot of the "turn-key" clocks seem to use them. The smaller tubes have gotten a bit more expensive, but not like the IN-18 or B7971.

Jim

On Saturday, October 5, 2019 at 8:52:24 AM UTC-6, Robert G. Schaffrath wrote:

Shortly after I wrote my previous post, I came across yet another ad for one of these 4-Bit QS30 clock modules and it says it uses a DS3231 clock chip. So that explains the accuracy. The ad also has a link to a PDF instruction sheet (in Chinese).

I am amazed there is enough of a market for these clocks that a Chinese firm went and designed several different modules. The QS30 module is a variant of an IN-12 module also sold. I've never been a fan of the IN-12's with their inverted "2" to create a "5". I would hunt down genuine Burroughs or National tubes instead (which would cost me dearly I am sure).

Robert

[Greg P]

Welcome back Robert.

Please if you can post some pictures of the NOS 7971 tubes you have.  I've and many in this group have never seen an NOS one.  Seems they're all pulls from the Ultronics boards.

[Robert G. Schaffrath]

Here they are. They are genuine Burroughs without the Ultronics branding. There is no darkening in the tube and the pins show no scratches indicative of having been inserted into a socket. IIRC (it has been 40 years), the vendor (Poly Paks? Meshna?) obtained them from a repair facility were they were spares for the Ultronics boards. They were sold as unused and not pulls:

Now besides those new tubes, I have in additional the six Ultronics tubes being used by my clock, this one used Burroughs tube that was installed on one of the Ultronics boards I purchased way back when. This one is different than any other B-7971 I have seen:

The difference with this tube is it has a post sticking up above the segment holder. I have no idea what the post does but none of the other tubes has it. Also, as I recall when I tested the tube out, it has a slightly darker red color than the Ultronics tubes. When I put it in my clock, I could tell the difference next to the other five tubes. It might have been that the tube had not "warmed" up or possibly the other tubes have mercury or some other additive that lightened the color slightly.

I have some other pictures of tubes I have that I will post in a new post.

Robert

[Jeff Walton]

The 7971s with the post are from early date codes.  There are several variations.  I have 8-10 with the posts.  Check the backs of the tubes.  Older tubes use wires and the newer tubes have embedded conductors. 

Jeff 

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[Jeff Walton]

Here are a couple examples of different construction:

 

 

 

 

 

The older B7971s used wires on the backplane.  The really early B7971s had the center post and some had full top insulators as well.  There may even be more varieties from some of the others that have collected these tubes.  Amazingly, I have never had a 7971 fail except for physical damage.

 

Jeff

 

 

 

 

From: neoni...@googlegroups.com [mailto:neoni...@googlegroups.com] On Behalf Of Robert G. Schaffrath
Sent: Sunday, October 6, 2019 12:51 PM
To: neonixie-l
Subject: [neonixie-l] Re: I'm Back: ZM1022 and B-7971

 

Here they are. They are genuine Burroughs without the Ultronics branding. There is no darkening in the tube and the pins show no scratches indicative of having been inserted into a socket. IIRC (it has been 40 years), the vendor (Poly Paks? Meshna?) obtained them from a repair facility were they were spares for the Ultronics boards. They were sold as unused and not pulls:

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[Robert G. Schaffrath]

Thanks for the pictures. I only have one post variety with the wires. All other tubes, the Ultronics and the NOS Burroughs, have the trace connections and are basically identical except for the Ultronics/Burroughs branding. None have the full round insulator.

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[Bill Notfaded]

They made less of the antenna variety from what I've seen. Most of mine don't have them.

Bill

I also have I believe a 1.06 version of that clock that runs off the mains. Mines running z566m red tubes.

Bill

[Robert G. Schaffrath]

With me it is the only B-7971 tube I have like that. It came from the first Ultronics board I ever purchased in the late 1970's. It came from Poly Paks IIRC. It was actually a bad deal for me. Apparently the board had been serviced which explains the genuine Burroughs tube that was on the board. The other tube is Ultronics (which I still have) and is defective. The #4 and #13 segments touch each other causing both to light when either is energized. The circuit board had jumpers soldered onto it and handwritten in fine tipped magic marker it said "modified for dummy 0". My parents joked at my expense that it was modified for the dummy (me). Why the Ultronic service center did not replace the defective tube rather than go through the effort of modifying the board escapes me. Especially since they replaced what I assume had been an Ultronic tube in the other socket. I could have had two Burroughs tubes with posts.

When I decided I wanted to get three more boards, I bought them from Meshna due to my bad experience with the other vendor. After I had those boards, I decided to splurge on the 6 NOS B-7971's. I still have one Ultronics board left that has the sockets still installed but no tubes. I used the other three for sockets and HV transistors to build my MM5311 clock.

[Jeff Walton]

Check out this thread for repairing the shorted segments:  https://groups.google.com/forum/m/#!searchin/neonixie-l/Shorted$20segment$20b7971/neonixie-l/w4YmXnY9dgE

Jeff 

-------- Original message --------

From: "Robert G. Schaffrath" <robert.s...@gmail.com>

Date: 10/8/19 8:47 AM (GMT-06:00)

To: neonixie-l <neoni...@googlegroups.com>

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[Robert G. Schaffrath]

That link is not working but a search of the forum turned this thread up:

https://groups.google.com/forum/#!searchin/neonixie-l/shorted$20segment|sort:date/neonixie-l/w4YmXnY9dgE/8o-AsZZyBQAJ

I assume that is the thread you were referring to. I'll have to give it a try. If the tube breaks then so be it. About all it is good for is making either an "A" (8 with bottom off) or "P" for an AM/PM indicator. 20+ years ago or so I stupidly cut off the pin for the #13 segment because it was shorted but it could be repaired and used again. Especially considering the value of the tubes it would be a minor inconvenience.

I'll have to dig the tube out this weekend and give the repair process a shot.

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[Robert G. Schaffrath]

It took some digging around to find it, but I did locate the Ultronics B-7971 with the shorted segments. This is a closeup picture of the short:

Then for some reason around 30 years ago, I decided to cut the #17 pin off which is connected to the #13 slanted segment that is shorted. Not sure why I did that or what I was thinking back then. If I can resurrect the tube, it would not be that big a problem to attach an extension to the remaining stub and make #13 usable again:

Finally, my 40 year old 6 tube clock in operation. I had not powered it up in a while. Still works! Mind boggling to think the tubes in this clock could be worth close to USD$900 now (It is covered in plastic due to the dust issues. I got tired of cleaning off the tubes when I wasn't even using it):

[Michail Wilson]

Robert,

 

I have come across a lot of tubes with this issue (not the cut off leg).

Although I have broken more than my share of tubes by dropping them, I have never broke a tube with a short.

 

I have over the years been able to smack the short out of them.  I believe you will find it is easier than you think it might be.  Of course you will see dollar signs flash in front of you each time you smack it.

 

Trying to look closely at your short, my suggestion would be to put the tube in a socket and smack the tube in a downward fashion on a table.  The socket being used to protect the pins and the nipple.  Also try smacking the face of the tube into your hand.

 

Michail Wilson

206-920-6312

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[Bill Notfaded]

I have never had a failure with a working B-7971 tube.  They are, if working, rock solid.  Unless you start with a messed up tube I would say they are some of the most stable neon tubes ever made.  Big, bad@55, rock solid tubes.  I'm sure cutting off pins or a rare overlapped cathode might be an issue.  I'd say if you had an overlapped cathode issue then definitely try the taped broomstick method and try to knock it loose because these tubes run and run and run as long as they don't have physical defects inside.  Ironically they are some is the best tubes ever made as far as I'm concerned.  They are bright and just work great.  Yeah... they're expensive these days but dang they're awesome!!!  I'm sure Michail and Michael will both concur... B-7971 tubes are some of the most awesome Nixie tubes ever made period.  They're really priceless now because no one makes them anymore.  Even the new age Nixie tube manufacturers aren't even trying alphanumerics.  These are it... and they're awesome!   Still running strong... Big... Beautiful!

Bill

On Sat, Oct 12, 2019, 10:51 AM Michail Wilson <M...@michail.com> wrote:

Robert, you

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[Robert G. Schaffrath]

Until now, I have never tried to fix the tube. I was the one who cut the pin off many years ago but also realize that when I did cut it, I could have purchased another tube for around USD$8 at the time (~25 years ago). As I already had 6 Ultronics tubes in my clock, 6 NOS Burroughs spares (which came with an original copy of the Burroughs data sheet that is packed with the tubes) and 1 used Burroughs tube (has the "antenna" in it), I did not see the need to go out and buy another. Of course fast forward 25 years and that tube could now command USD$100 if it can be fixed. I suspect a lot of damaged ones got thrown out in the past because they were cheap to replace. I just happen to be a pack rat and keep stuff like that LOL.

I do not have any spare sockets to try M1's suggestion. I have a large wooden dowel that I can duct tape the tube to or even a 2x4 if necessary. Soldering a small extension to pin #17 would not be an issue though I have thought that I might swap it for one of the tubes on my clock since it does not use segment #13 and if segment #4 is repaired then it should work fine leaving me a fully intact Ultronics tube.

I may make the attempt today to see if I can free it. Definitely a scary prospect of shattering the tube.

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[Michail Wilson]

If you go the route of attempting to smacking it…   First try smacking into the palm of your hand.

 

If you’re in the USA and want to try, I have no problem sending you a socket for free.

 

Michail

 

From: neoni...@googlegroups.com [mailto:neoni...@googlegroups.com] On Behalf Of Robert G. Schaffrath
Sent: Sunday, October 13, 2019 5:46 AM
To: neonixie-l
Subject: Re: [neonixie-l] Re: I'm Back: ZM1022 and B-7971

 

Until now, I have never tried to fix the tube. I was the one who cut the pin off many years ago but also realize that when I did cut it, I could have purchased another tube for around USD$8 at the time (~25 years ago). As I already had 6 Ultronics tubes in my clock, 6 NOS Burroughs spares (which came with an original copy of the Burroughs data sheet that is packed with the tubes) and 1 used Burroughs tube (has the "antenna" in it), I did not see the need to go out and buy another. Of course fast forward 25 years and that tube could now command USD$100 if it can be fixed. I suspect a lot of damaged ones got thrown out in the past because they were cheap to replace. I just happen to be a pack rat and keep stuff like that LOL.

[Robert G. Schaffrath]

Well I tried smacking it around and the short was fixed! Except now I find a different problem that was not present before:

You can see the slight bend in the bottom segment that had been shorted. However, this should be displaying an 8 not a 6. The #2 segment is not lighting up and the #6 will flicker a bit if I tap the tube. I am guessing some connections have come loose. I have a tiny Tesla coil device that I will try out with the tube on each pin and see if I can figure out what is going on. But I can definitely vouch for the banging method to fix the shorts.