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color classic dead screen

Chopsticks

Well-known member
ive recently dug out my old color classic and awhile ago it was working, the logic board has been recapped about 2 years ago however upon turning it on now I get the startup chime and it appears to boot/read from floppy disk. however the display is completely dead.

I hard replaced 90% of the capacitors on the analog board (waiting on a few values I didn't have to arrive in the mail atm), I have also checked all the transistors and FETs for shorts with no issues noticed so far. the I have replaced the opto isolators in the switch mode PSU section (though I wouldn't expect to boot or have normal voltage levels on the +5 and +12 is that was an issue).

as there are no schematics for this I was wondering what would be the best course of action to take. one thing I have noticed is the PTC used for degaussing gets extremely hot (part number PTH45IC at location RP12). my next changed Are likely to be the following however im hoping someone can point me in a more direction location/idea as to what I should example and/or replace:

TDA8172 - TV Vertical Deflection circuit IC
LM2418T - CRT driver IC
TDA8145 - East/West correction IC
TDA4605-2 - Switch mode PSU IC's x 2

im not that well versed in CRT circuity, much more skilled at logic board repair to be honest

any insight, ideas, or help would be greatly appreciated if avaliable as id like to restore this to a working state being how 'rare' these models are in the wild
 
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