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12" Mono CRT - Just picked this up from eBay *advice needed*

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First post, by 4xtx

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Hi all,

Not too sure what this is - but it was cheap and I was hoping to get it working with one of my many Mono, MDA, Herc cards.
Google-ing the model number makes me think it is a generic mono green phosphur. I've never heard of "Sandy" tubes before either..

It has a non-AU 3 pin power plug which is easy enough to change over and it appears to be 240V/50hz.
First thing I did when it arrived was whip off the back and see if anything was obviously damaged, bulging or infesting (bugs!) - nope, looks mostly unscathed.

Before turning it on I'd like to do some checks, tests but have never really thought about CRT's before.
Can anyone give me some advice on what to look for or test before safely switching this baby on?

I've also tried calling some local "electricians" in my area but not getting anything other than a long pause and sometimes a laugh.. 😀

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YT: https://www.youtube.com/@techdistractions

Reply 2 of 3, by SSTV2

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4xtx wrote on 2022-05-10, 05:36:

Before turning it on I'd like to do some checks, tests but have never really thought about CRT's before.
Can anyone give me some advice on what to look for or test before safely switching this baby on?

If the previous owner has already tested the monitor, then you can try to turn it on, but if the power has not been applied to it for more than 15 years, then there is a chance that the dielectric layer in the capacitors has partially dissolved in the electrolyte. If a high voltage was to be applied to the capacitor in such a condition, it would just short out. I'd be most concerned about the ~400V PSU and ~160V B+ caps.

Google "capacitor reforming" to learn more about this topic and how to prevent catastrophic shorts.

4xtx wrote on 2022-05-10, 05:36:

I've also tried calling some local "electricians" in my area but not getting anything other than a long pause and sometimes a laugh.. 😀

I'd bet they would be stumped upon receiving such a device 😀

Reply 3 of 3, by 4xtx

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SSTV2 wrote on 2022-05-10, 12:36:

Google "capacitor reforming" to learn more about this topic and how to prevent catastrophic shorts.

Thanks! This is the type of thing I was thinking about 😀

YT: https://www.youtube.com/@techdistractions

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