Minimum ongoing CRT usage for long term preservation

[andykara2003]

I have a group of CRTs that I want to keep going long term. I’ve heard that it’s a good idea to periodically use them as not doing so can be detrimental. Is that true - or another internet myth? And if it is true, how often would they need to be turned on and for how long?

[Syntax]

Its a load of it.

Keep them dry and away from direct sunlight and they are fine. Lowest humidity possible.

Running things periodically to warm them up and remove moisture is a thing yes, but proper storage should come before it.

[Ikaruga11]

It's perfectly fine to not use them. The key is keeping them dry and indoors where the temperature is stable (preferably 60-70*F), and the screen not being exposed to light.

[andykara2003]

Thanks both. All my stuff is in an un-tanked cellar. There’s a decent dehumidifier down there keeping things at 50 percent humidity and between 55 and 65 degrees. The dehumidifier pulls about a bucket of water a week out of the air. It has enough power to take the room down to 40 percent if I wanted, but I’m worried that might cause an unforeseen issue, an I’m artificially dragging the moisture out of the room rather than having a naturally attained atmosphere. So my new questions are:

1: If I take the humidity down to an even lower level (40%), is there a chance that I’ll damage the electronics due to using a dehumidifier?

2: My room goes down to 50 degrees in the winter - Is it definitely a well known/established fact that electronics like CRTs need to be ideally kept above 60 degrees? In which case I use a heater to set it to a minimum of 60 degrees.

[BuckoA51]

I heard certain types of capacitor benefited from at least periodically getting some voltage through them?

Again, could be total nonsense though.

[buttersoft]

Depends on the tube, and how pure the vacuum inside is, how well made and how good the materials. A lot of arcade tubes have a problem being left unsused and the cathodes start oxidising. This results in discoloured, blurry and sometimes even silghtly warped displays. It even happens to the ones used by Kaga Denshi/Sega/Nanao from the 80's and early 90's. This is the best possible use of a rejuvenator, about the only time a rejuvenator really works properly, but even then it has to be hard on the tubes. Better to turn them on once or twice a year.

Most newer tubes seem ok, but i'm sure there will be instances like the above.

[ChuChu Flamingo]

I heard certain types of capacitor benefited from at least periodically getting some voltage through them?

Again, could be total nonsense though.

I don't think it is nonsense. A mr carlson's lab topic on capacitors that were in use every now and then lasted longer vs ones sitting unused. I can't find it right now but below is a topic that explains it pretty well.

https://www.robotroom.com/Capacitor-Sel ... rge-3.html

I know many old radio/amplifier guys use a variac on stuff for this reason to self-heal the capacitors. Even more so if it has been powered off for long periods of time (talking years). It helps mitigate the risk of something that has not been powered on in who knows how long giving u the magic smoke. It seems to play a more important role in stuff with high voltage (like power supplies and other areas of high heat)

good information butters.

tl;dr I wouldn't worry about it, maybe power it on 6-12 months. Hard to say how much longer it would last. Capacitors going bad does kill other components, but other stuff can die for no reason due to age as well. "All creature will die and all the things will be broken. That's the law of samurai."

[andykara2003]

Thanks guys, some very knowledgeable people here. Once or twice a year is no problem as I'll be using them at the very least once every couple on months. The only remaining issues are humidity and temperature. I'm thinking I might take it down a few percentage of humidity to average about 45%.

My last question, then, is about temperature. The temp in there is 13C which is 55 farenheit. I think this a bit low? If so, I'll get an accurate dedicated probe thermostat to control a heater to get a static, even temperature. What would be the absolute ideal temp, considering I'll have fine control over this?

[Taiyaki]

If you're idea is to store them for the future then pack them really well all around (to prevent any dust build up). If they're going somewhere where other items might get stored on top definitely add protection with bubble wrapping too imo. Make sure it's not in an overly humid or overly hot area (so no attics or basements if possible), definitely not in direct sunlight of course.

Personally I'm not much of a believer in the powering them on from time to time rule, because I've seen brand new crt's out of box that had been in storage for over 2 decades and still came out looking like new (the insides, including capacitor readings). How many decades do you intend to store them? If capacitors go bad you just replace them, for all you know they could go bad anyway even when bothering to power on and off at certain intervals. To be honest I'd worry more about taking them back into working environment just for stress tests and back to storage rather than just letting them hibernate fully, capacitors may theoretically benefit but other components may not.

Although might sound really maniac level to mention this, the ideal way to protect yourself would be to store several working units of the exact same models. That way if you run into problems with components later some decades from now, you're more likely to be able to piece together a fully working unit.

[gray117]

Dryness, medium consistent temperature. 13 degrees is probably ok - dryness and consistency in temperature is the key: prevent any condensing on (metal) parts that cool or heat at different speeds. If you've got anything you're keen to preserve (bvm?) try sealing in acid free cardboard lined wooden box - think that's what super keen comic people look to - the wood does an extra job of sealing off, absorbing moisture and moderating fluctuations - rubber seal on the lid and an extra silica pack in there could help draw away any trapped moisture.


If powering up in a different location perhaps allow a day to acclimate... but yeah you know - longer this goes on the more it's descending into best chance/prayers/incense burning

...


Specific bits:

Capacitors are a common weakness - but they're relatively easily diagnosed, sourced and replaced. Same for resistors. Exception might be anything to do within a flyback where diagnosing/repairing is more of a pain/dangerous.

Tricker bits to indentify/substitute can be transistors/diodes... as long as you have a good service manual you can probably find something suitable, although testing this could be somewhat of a risk ... some of these may have faded out of common usage/stock so finding or constructing the equivilant may be more tricky...

And then anything that maybe some kind of custom chip and/or susceptible to eventual bit rot... but that's pretty much an unsolvable unless you're cleverer and more dedicated than most... or can enlist such help (and test and solve these issues ahead of time)...

[andykara2003]

Thanks all for the amazingly detailed advice. I've set the temperature to a stable 17C (62F), and the humidity to a steady 45 percent. This should hold through the year. I also have a few backups for parts etc. Lots of good info on this thread to refer to in the future..