I’m somewhat experienced with proper high voltage stuff and know what precautions to take. But yes it’s always good to tell people these things, not everyone is aware after all. Yeah, I planned on replacing the capacitors anyways at some point, preemptive maintenance is always good. My Intellec 8 is waiting on some new caps as well. I’ll pull out one of my scopes some time this week and take a look. I was planning on reverse engineering the whole thing as well and creating schematics, this would make Troubleshooting in the future a lot easier. Another thing I’ve wanted to check is the voltages, might be running a little high since a couple decades ago the grid voltage was increased from 220 to 230V, which should be still within the tolerance of +-10 but I’d rather check. Since I was planning on reducing current anyways reverse engineering would be a good first step. I’ll post the schematics when I’m done. Paul Andrews schrieb am Dienstag, 14. November 2023 um 20:36:58 UTC+1:
> Might be worth checking some voltages - bearing in mind that those > voltages are likely to be lethal if they short through you. If you've never > done that kind of thing you should be very cautious. You should have an > isolation transformer and plug the sign in to that. > > Power supplies can deteriorate over time, specifically the capacitors dry > out if they aren't used and the voltage becomes unstable, given that these > tubes worked better just before you bought this, it is making me wonder if > this is a problem you are having. If you have an oscilloscope, that would > be better than a multimeter so you can see if any mains frequency is making > it through. You could probably figure out what the voltage should be by > checking the resistors on each cathode and comparing them with those on the > datasheet I posted a link to. There is a good chance that the tubes are > being multiplexed, which would mean that the resistors would typically be > lower for a given anode voltage. > > Can you post some close-ups of the circuit board, transformer and part of > the wiring loom? > > On Tuesday, November 14, 2023 at 1:55:39 PM UTC-5 Magnedyne wrote: > >> I have opened it up and removed all of the crumbling foam it was filled >> with. Lucky me, it wasn't foam which turned to goop. >> Well, the tubes are not socketed, instead they're directly soldered in. >> So definitely not corrosion. Seems like it's the tubes. >> >> [image: IMG_20231114_194941.jpg] >> >> Paul Andrews schrieb am Dienstag, 14. November 2023 um 16:09:22 UTC+1: >> >>> Regarding the yield? Just my (and others) experience with 'new old >>> stock' tubes. I don't have any information on what the yield was at the >>> time of manufacture. Its easy to rationalize a low yield because of the >>> large seal between the glass and the body, but that would just be guesswork. >>> >>> Interesting that the affected tubes were better in the original photos. >>> In the U.S. we have a product called 'deoxit' that is used to fix old >>> electrical contacts that may have some dirt/corrosion on them. It is just >>> sprayed on the contacts and then the device is used as normal, though I >>> don't know what the breakdown voltage is of the product. I have used it in >>> old vacuum tube devices. >>> >>> On Tuesday, November 14, 2023 at 12:56:18 AM UTC-5 Magnedyne wrote: >>> >>>> >>>> Alright, thanks for the tips. I’ll see what I can do. Not doubling the >>>> current on other tubes should be obvious, if anything ill modify the >>>> circuit on those to run on like 60% current or something, don’t want those >>>> to wear out after all. How long would I double the current on the affected >>>> tubes? I’m guessing until it lights up entirely, but what if it doesn’t? I >>>> don’t want to risk damaging any tubes further unless I have access to a >>>> replacement. Interesting regarding the yield, where did you find that info? >>>> Paul Andrews schrieb am Montag, 13. November 2023 um 22:55:13 UTC+1: >>>> >>>>> Because all the segments are in the same plane, it is possible that >>>>> they could all get deposits equally, so increasing the current may work. >>>>> Yes, the current is controlled by a resistor. The documentation I linked >>>>> you to gives the recommended current for each segment. To try to >>>>> re-condition the segments I would double the current, but I would only do >>>>> that with the affected tubes. >>>>> >>>>> These tubes are known for having a low yield so it is possible that >>>>> the affected tubes have other problems, such as outgassing. I would be >>>>> very >>>>> careful when removing them from any socket they may be in to avoid >>>>> breaking >>>>> a seal between the pin and the tube. >>>>> >>>>> On Monday, November 13, 2023 at 4:22:00 PM UTC-5 Magnedyne wrote: >>>>> >>>>>> >>>>>> Furthermore I should mention that the partial glow does not affect >>>>>> only specific elements of the tube but any element inside the tube. >>>>>> Can this be caused by deposits? >>>>>> Nicholas Stock schrieb am Montag, 13. November 2023 um 21:56:10 UTC+1: >>>>>> >>>>>>> WHAT A FIND!!! OMG. I didn't even know there were smaller versions >>>>>>> of the ZM1350 (shame on me!). >>>>>>> >>>>>>> The tubes with the partially lit segments can probably be revived >>>>>>> with a little extra current... just be careful not to burn them during >>>>>>> the >>>>>>> healing process (if it works..). >>>>>>> >>>>>>> Wow.. >>>>>>> >>>>>>> Welcome to the group, >>>>>>> >>>>>>> Nick >>>>>>> >>>>>>> On Mon, Nov 13, 2023 at 12:07 PM Magnedyne <miro.s...@airgrips.de> >>>>>>> wrote: >>>>>>> >>>>>>>> Well, this serves as my introduction and and as a thread about a >>>>>>>> beautiful sign I just picked up. >>>>>>>> Firstly something about myself. >>>>>>>> I’m a 17 year old collector and (hobby) historian of vintage >>>>>>>> computers, my interests are mainly minis, mainframes, early micros and >>>>>>>> kit/diy computers. But I’ve got a few other different bits and bobs >>>>>>>> throughout the history of technology as well. >>>>>>>> Now back to the reason I joined this group. >>>>>>>> I came across an absolutely beautiful Telefunken advertising sign >>>>>>>> for the, frankly underdocumented, Telefunken Varisymbol tubes. They >>>>>>>> were >>>>>>>> Telefunkens response to the Burroughs 7971 alphanumerical tubes. These >>>>>>>> were >>>>>>>> only sold for a very brief amount of time and exclusively in Europe. >>>>>>>> Interestingly these are flat like panaplex tubes and the anode is >>>>>>>> not a grid, but a coating on the inside of the tube. These are the >>>>>>>> earliest >>>>>>>> gas discharge tubes, well the ones I’m aware of anyhow, which used >>>>>>>> such a >>>>>>>> coating. >>>>>>>> The sign is a handmade one off which was lugged around to fairs to >>>>>>>> advertise the Varisymbol to potential Customers. It implements all >>>>>>>> three >>>>>>>> sizes of the Varisymbol ZM1350 ZM1360 & ZM1370. It can alternate >>>>>>>> between >>>>>>>> „TELEFUNKEN“ and „VARISYMBOL“ at four different speeds. Switching >>>>>>>> between >>>>>>>> the sign reading „TELEFUNKEN“ three times, then „VARISYMBOL“ three >>>>>>>> times >>>>>>>> and the sign reading „TELEFUNKEN VARISYMBOL TELEFUNKEN“/ „VARISYMBOL >>>>>>>> TELEFUNKEN VARISYMBOL“ is possible as well. Unfortunately three tubes >>>>>>>> don’t display quite properly. I’m hoping it’s just the electronics, I >>>>>>>> haven’t had time for a detailed diagnosis yet. Even if it’s the tubes, >>>>>>>> it >>>>>>>> seems to be the most common type at least, the ZM1350 which seems to >>>>>>>> have >>>>>>>> popped up most often in the past. >>>>>>>> Any further info about the Varisymbol is greatly appreciated. >>>>>>>> Cheers, >>>>>>>> Magnedyne >>>>>>>> [image: IMG_0026.jpeg] >>>>>>>> >>>>>>>> [image: IMG_0025.jpeg] >>>>>>>> [image: IMG_0021.jpeg] >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> -- >>>>>>>> You received this message because you are subscribed to the Google >>>>>>>> Groups "neonixie-l" group. >>>>>>>> To unsubscribe from this group and stop receiving emails from it, >>>>>>>> send an email to neonixie-l+...@googlegroups.com. >>>>>>>> To view this discussion on the web, visit >>>>>>>> https://groups.google.com/d/msgid/neonixie-l/20e32d2c-3ac1-4656-b532-77b22f6a35f1n%40googlegroups.com >>>>>>>> >>>>>>>> <https://groups.google.com/d/msgid/neonixie-l/20e32d2c-3ac1-4656-b532-77b22f6a35f1n%40googlegroups.com?utm_medium=email&utm_source=footer> >>>>>>>> . >>>>>>>> >>>>>>> -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to neonixie-l+unsubscr...@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/838699da-4add-432f-ac13-8d70769f0713n%40googlegroups.com.
