Philips CM8833 whining problem
Hi all,
First post here, im looking for help/advice on a Philips CM8833 that has been stored in my garage for a good long while. Well i pulled it from the garage the other day as i was testing a Neogeo Aes which i bought at a bootsale. Anyway i hooked it up and got a loverly picture and a high pitched whine. I thought due to its age this was proberbly normal. Continued testing and everything was fine. But when i turned off the neo geo i forgot to turn off the monitor.
3 hours later, i realised my mistake and rushed to it. But alas the monior no longer displays a picture. Ok so here is where i need advise, i removed the chassis, (im an experienced arcade engineer and know the correct disscharge procedures) i tested the transistor {HOT} and found that the middle was shorting to ground but after i removed this the short was still there. I checked the poly caps c470 and c469 which also showed direct shorts.
I also tested the damper diaode D467 but this was ok and no short. I tested around the lopt and found that 3 points around this were shorted to ground. I removed the lopt and all shorts went away. So im kinda thinking i need a new lopt, but im worried that i may have missed somethin or that the new one may break when if i put one in. Just for your info i powered the psu board not connected to nothing and its not whining and its giving the right voltages.
Any advice would be great.
Just so you know i know how to discharge monitors but this was to send them away for repair. This is the first time i have ever attempted to fix one myself, mostly a confidence thing 😜
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