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-   Direct View (single tube) CRT Displays (http://www.avsforum.com/forum/64-direct-view-single-tube-crt-displays/)
-   -   Good to turn on unused CRTs once in awhile? (http://www.avsforum.com/forum/64-direct-view-single-tube-crt-displays/1527353-good-turn-unused-crts-once-awhile.html)

P719C1 04-14-2014 04:30 PM

Been awhile since I've posted here...

I have a few (ok, I'll admit it, more than just a few) CRT TVs and monitors.

The ironic thing? I barely watch TV at all anymore, and mostly just use my laptop computer on my couch.

Certainly I can't be the only person in the world like this.

I remember reading awhile back that it's good to turn them on every once in awhile if they are not regularly used. Is there any truth to that, or is this more likely to cause "wear" or a sudden failure than just leaving them off and unused for an extended period of time (1-3 years)? I'm wondering with the inrush current to charge up the anode cap every time it was discharged from long-term non-usage if that is more likely to affect cold solder joints or any components themselves. Is time the real killer, or just usage? I know that a constant state of being powered on would theoretically yield maximum hours of usable service.

JA Fant 04-14-2014 06:17 PM

Yes. Especially if your CRT is a Sony. Occasion power up/power down will degauss the picture tube and extend its lifespan.smile.gif

Floydage 04-15-2014 09:27 AM

A poster here claimed there's a tiny amount of moisture that can leak inside the CRT over years of non-use, therefore needs to get burned off via power-up. I don't know if that's true, seems to defy the meaning of a vacuum tube...
But turning it on only once every few months isn't enough inrush current wear&tear to worry about so I would err on the side of caution and fire them puppies up every now and then.

Ratman 04-15-2014 01:06 PM

Moisture cannot build up in a CRT.
Degaussing has nothing to do with extending lifespan of a CRT whether it's a Sony or BrandX.

Storage and non-use over years may cause capacitors to dry out. This is not limited to TV's, but any electronic gear.

IMO, if you have a CRT (or a few) that only get used once a year (or three)... sell it (them) while it still works. wink.gif

P719C1 05-19-2014 06:24 PM

Quote:
Originally Posted by Ratman View Post

Moisture cannot build up in a CRT.
Degaussing has nothing to do with extending lifespan of a CRT whether it's a Sony or BrandX.

Storage and non-use over years may cause capacitors to dry out. This is not limited to TV's, but any electronic gear.

IMO, if you have a CRT (or a few) that only get used once a year (or three)... sell it (them) while it still works. wink.gif

But conversely, over-degaussing can kill a CRT. In my youth and early teens I was obsessed with degaussing, and I think that's how I killed my family computer's monitor . . . this was right about the time it was getting hard to find a new CRT monitor, and before I knew Craigslist and the like existed.

You're right though, time for me to start appreciating my CRTs or hand them off to someone who will. Crying shame to just have two FW900s sitting there for months on end. eek.gif

Ratman 05-20-2014 05:24 AM

Quote:
Originally Posted by P719C1 View Post

But conversely, over-degaussing can kill a CRT.
Nah... internal degaussers typically trigger with every "power-on". Constant/continual (obsessive?) power cycles probably do more harm than degaussing.

Floydage 05-20-2014 08:56 AM

Obsessive [internal] degaussing can fry the degausser circuit if the circuit doesn't have time interval and/or thermal protection. The CRT device would probably still work but be susceptible to guassing problems. I have an old TV like this but it's fine after providing an external degauss pulse as long as I don't rotate the TV afterward. [it's unlikely that the degauss coil gets fried, just the pulse circuit]

P.S. Could also blow the internal line fuse.

EscapeVelocity 05-20-2014 08:59 AM

I used a Panasonic 20" (or so) TV this winter. For the first week or two I had an issue with magenta in the lower portion of the screen, visible on white fields. However the issue worked itself out over time with use. smile.gif

Mark12547 05-20-2014 06:18 PM

Electrolytic capacitors would be my primary concern: if they aren't used for a very long time, the dielectric "film" dissolves and needs the voltage to keep built up. I don't know what is a good duty cycle to keeping them in shape, but I would probably want to run the device for at least ten minutes every month. If someone else has a better idea, so much the better.

 

I don't think degaussing would be an issue; I don't think the internals get significantly magnetized without current actually flowing, and the tiny bit picked up from Earth's magnetic field would be quickly undone by a power-on degaussing.

 

Now frequent powering-ons would be potential problem-causers because of the heating and cooling of the tube filaments (at least the filament of the CRT if it doesn't have any other vacuum tubes) because that causes stress from expansion and contraction of the filament and, do it often enough, the filament becomes less uniform, gets hot spots, and finally breaks.


bobafetthotmail 05-21-2014 04:05 AM

Well, checking that stuff in storage is still operational at regular intervals is crucial if you don't want to waste space keeping devices long dead (and discover this only when you needed them).

 

As for the rest, when it goes it goes. As simple as that. Worrying about making it last longer is a waste of time as there are no standard procedures nor decent knowledge about the specific components in each specific device. I have seen boards with unbelievably crappy capacitors that refuse to die after 15 years of service and repeated abuse, and supposedly long-lived solid-state capacitors that die within months.

 

More often than not all you can do is follow opinions and rumours that are pretty much superstition.

And that's the same as my granma that was terrified to see an open umbrella in a home or to see a hat on a bed (both things seem to bring "bad luck" according to local folklore).


Floydage 05-21-2014 03:13 PM

Yeah that entire component thing makes me wonder. Raw parts are kept in distributor storage for who knows how many years, not to mention eBayer-types. I think the key word here is storage - there are environmental specs for components in regards to temperature and humidity although it's not as stringent as one would think.


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