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Hello all. Perhaps a good soul from this forum can advise on the following issue with one of my ELMO ST1200 projectors. The projector is emitting a high pitched tone via the speaker. Has any one encountered this before and if so did you solve the issue, and can you advise how you did it? Thank you all.
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Hi Mark,
Often this can be solved by working all the switches associated with the audio circuits and breaking built up oxides on the contacts.
One time it didn't for me after many tries. In that case it was track 2 on an ST1200HD. I managed to get a schematic for the sound board (now posted in the warehouse here). I reasoned (guessed?) that the only semiconductor device associated only with that track was the pre-amp IC, so I replaced it (and every other one of the same type) and the problem went away.
-it worked out, but it got ugly! Maybe the worst part is I wasn't sure I was right until all the work was done and the board re-installed in the machine.
I hope for your sake it's just switch oxides! -
Outstanding Steve, I shall be working those switches and maybe offer them some switch cleaning fluid.
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