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Ctm644 Vr402 pot replacement

Started by JohneBravo619, 15:01, 24 February 21

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JohneBravo619

Hi


I have been having a lot of trouble with brightness on my Ctm644 monitor. On opening it up it looks as though the sub bright pot has been damaged.


Is there any particular replacement for this?


Also, I can discharge the anode but is there any particular caps that still hold a charge?


Thanks


John

Bryce

Quote from: JohneBravo619 on 15:01, 24 February 21
Hi


I have been having a lot of trouble with brightness on my Ctm644 monitor. On opening it up it looks as though the sub bright pot has been damaged.


Is there any particular replacement for this?


Also, I can discharge the anode but is there any particular caps that still hold a charge?


Thanks


John

It's a standard 5K Linear trimmer pot. You should be able to find them at any electronics supplier, but they look completely different these days. They are closed blue boxes instead of an open design.
There are a few larger caps on the PCB that I would check that they are discharged before poking around.

Bryce.

JohneBravo619

Thanks Bryce! Will take a look!

JohneBravo619

Would you possibly have a list of the capacitors that normally need replacing... May as well give it a full service while I'm there... 😁

Bryce

I don't have a list, but if you want to start swapping capacitors, it's the larger electrolytic capacitors that would most likely need to be changed.

Bryce.

JohneBravo619

Found the list. Thanks again Bryce!!


Thanks

JohneBravo619

Back again... So.... Replaced the trim pot.. Got nothing... Tried to adjust it but think there is something else causing it not to work. Screen still has static and makes a noise to know its on. I then stupidly knocked the h hold trim pot while looking around....turned it on without knowing and now it does not come on at all. Anyone know which capacitors/resistors would have been affected if the h hold trim pot was not properly connected?
Thanks

Bryce

None. I think you may have a problem with the LOPT.

Bryce.

JohneBravo619

So you think that with damage to the h hold pot the LOPT was affected? It was giving a static feel to the screen before this happened...

Bryce

Quote from: JohneBravo619 on 15:44, 17 March 21
So you think that with damage to the h hold pot the LOPT was affected? It was giving a static feel to the screen before this happened...

No, I think the LOPT has died of it's own accord, unrelated to the Pot. Is it still producing static charge?

Bryce.

JohneBravo619

No....seems dead...no static or sound. Any ideas on where i can get a replacement Bryce?..... don't want to get rid of this monitor... :(


Thanks for all your help!

Bryce

From another CPC monitor. I don't know of anyone selling this part.

Bryce.

JohneBravo619

Bryce...silly question....but would a ctm644 mk1 flyback be the same as the one in the mk2 ?

Bryce

I think so, but I'm not 100% sure.

Bryce.

JohneBravo619

Thanks Bryce. Not sure if anyone else knows but i have model 3714009 and i have an offer for a 3714016. Anyone know if this is compatible? Maybe just a newer model??

JohneBravo619

Bought it anyway....It was new on ebay from someone who bought them for their business monitors back in the day. Fingers crossed.

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