Commodore 1084 tube shut down

qq1975b

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Hi everyone.

I have a Commodore 1084 monitor (not S) which sometimes turned off. I thought maybe it was the power switch, so I decided to replace it and by the way, replace all caps.

So I did that and my surprise is that it is still doing that but I noticed something I didn't before. The power is ON but the tube is OFF. I don't know if this is a known to anyone and the way to solve it.

Thank you.

This is my monitor: https://gona.mactar.hu/Commodore/monitor/Commodore_monitors_by_model_number.html. (1084 monitor).
 
with a little hit it works again but maybe after some time, it shut downs again (maybe)

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transformator ht is dead

HT? which part is it? if you know. Thank you.
 
high voltage, we must check the transistor near this transformer, it is mounted on an aluminum plate
 
Ok. So, won't you know by any chance a compatible part? o specs I have to look for on Mouser? I found the caps list but not a service manual with parts and I do not know which transistor I can buy.

Thank you again for the help.
 
with a little hit it works again but maybe after some time, it shut downs again (maybe)

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Sounds like it could be dry/cracked solder joints around the flyback transformer. You may be able to reflow the joints and fix it.
 
Beware, there can be some large residual voltages in the FBT circuitry when the power is disconnected, really a task for a professional if you do not know what you are doing.
 
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I resoldered all the solder joints of the flyback and it seems after 3 days of testing, that it works ok.

Thank you!
 
I resoldered all the solder joints of the flyback and it seems after 3 days of testing, that it works ok.

Thank you!

Hello

Same CRT, same problem, same action, same result :D

thx for this post, this is THE rebirth of my 1084 o/
 
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