Deltatest

Problem: all the numbers of each single valve are always on, as you can see in the following pictures.
Someone can help me?
Tanks
Giovanni

Well, since nobody else answered and I am fairly well acquainted with nixie tube stuff I'll take a shot.
This could be something as simple as a short or an easily replaceable part(resistor, capacitor etc) or something as complicated as an unobtainable IC which has the potential to render this whole thing useless.
I Imagine these work similarly to Bench meters of the era, they pick up the signal, convert it from analog to digital and from there the fun begins. There are a ton of Integrated circuits which are obsolete nowadays making this thing tick.
It will take somebody with electronics knowledge and the proper tools to even attempt to diagnose it.

What I would do, If I were you , is I would search for a manual/schematic for this. Maybe it is displaying an error code by having all digits lit up. Also, you should begin the diagnostic by checking the power supply lines and a visual inspection of the board. It all depends on how much time you're willing to invest into it and if you can(or have somebody else) work on it. Maybe you could contact Omega for a manual? Lucky guess.
P.s I've never worked on old watch repair equipment and I'm just taking an educated guess.
I hope you'll be able to work something out.

Hi, thank you.
I’m looking for manual but nothing...
I’ll try to contact Omega.
All boards seems good...

I'm no electronics expert either but have rebuilt Revox and Nagra Reel to Reel gear from this era. Virtually every fault disappeared when I replaced all the electrolytic capacitors. In the end, it was easier to replace all of them than try and trace which ones had gone bad as they were probably all due to fail anyway after 50 years, plus caps cost pennies The other passive components, transistors and ICs are less problematic.

Obviously, be very careful with this stuff as the caps often store charge and can recycle on their own. Plus, any valve gear can run very high voltages. My hi-fi amplifiers have 600V in them (6C33C valves).

Good luck, Chris

Ok, at a first glance everything looks fine. It's surprisingly clean, given its age. I did a quick google search on the ICs and most of them seem to be available, that's good news.
There are a ton of latches and logic gates in this thing, no surprise. I'd even say that it's built 85% like a nixie tube bench meter. It's also incredibly beautiful, I love the hand-drawn traces.
As ChrisN said, be careful with it. The ignition voltage for nixie tubes is typically 170V DC.
At this point I can only recommend one solution, find somebody who knows his electronics because this will require a medium to high knowledge level in the field. This is definitely not a job for a newbie. The operation of the logic gates and latches will need to be checked(I suspect that is the culprit, something might be pulled high somewhere or an IC is dead)
Parts will not be expensive. Labour will be. An oscilloscope will also be required but any self-respecting semi-pro will have one.

If you want to tackle it yourself and you do have some knowledge in the field, I can provide a few tips:
1. Check anything with a heatsink. Heat ages components faster.
2. If you have a multimeter, check the transistors with the diode test mode, as 2 pin combinations should behave like diodes.
3. Replace any capacitors near heatsinks.
If I were to start on these, the big blue radial caps would be the first to go, especially since they are electrolytics.
4. Check fuses and power lines
If it lands in the right hands, I'd say this has a very high chance of being fixed. Maybe it's something as simple as a capacitor or a fuse.
Anyway, I wish you good luck and make sure to keep us posted. This is not something you see every day.

Hello, it is an old threat, but since I am currently working on those equipments and serviced another brands, I will advise first to check the 5 Volts on the Pin 5 SN74141 BCD-to-decimal decoder. If it is OK, then replace all 3 of them on sockets. Also check the 3 transistors and replace together with the ICs if needed.
The SN74141 BCD-to-decimal decoder driving the tubes and can cause this kind of fault.
There is also a lot of Handmade wiring on the 050-28 & 050-29 Digital Plug in sockets. If they are bend can cause short.
Make a Visual Inspection as well.
Good luck
Theo

Was gonna say, those SN74XX chips are simple logic gates, dime a dozen.

Here's what Google AI says:
"If all the digits in a nixie tube appear lit up at the same time, it likely indicates a problem with the tube itself, rather than a wiring issue. This is often due to cathode poisoning, where sputtered material on the tube's glass interferes with the ability to extinguish digits. This can happen as the tube ages, especially if some digits are used more frequently than others. "

That'd be my guess considering how old it is. They are not quite a dime a dozen, but available. While yours say Philips ZM1000, they were sold under a number of brands, Amperex being the most common. Same number tho. I see them available for about $50+ each.

Edit, Google AI might be hallucinating. Reading more about it, cathode poisoning (the numbers are the cathodes) makes a specific number dimmer than it should be. Another page indicates that cathode poisoning can cause ghosting, where numbers that shouldn't be lit appear as they are. You could have an extreme case.

BTW, while electrolytics are often the first thing to go, I only see one in your box and that's the huge can. If it fails, you will see some black gum somewhere around the seal or lead exits. My bet is still on the tubes themselves as they do wear over time and use.

I would 2nd that opinion, if the thing has been left running in a commercial environment the tubes will either be flat ( low emission) or most likely poisoned.
People go on about electro's failing and yes that's a valid thing on very very old valve gear and 90's Asian sourced caps but yours aren't, but with quality components this is less likely to be the issue in your case though as a precaution some of the caps in the power supply might benefit from a refresh but I doubt they are causing your failure to light correctly ( you need to check power supply rails HT and LT ).
I doubt there is any thing else major going on however all the parts are cheap and available as others have mentioned.

A cathode poisoning will have an Impact in all Tubes. However, the 1st one which is not lit at all, so is not affected.
The number of impacted Tubes represents the number of the SN74141 BCD-to-decimal decoders drivers and the transistors which applying 170 Volts to the tubes, and here is the starting point for troubleshooting.
From all my nixie tube Timegraphs I have never faced a defective Tube.


Best Regards
Theo