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Mitsubishi TV model CS35MX1 weird audio problem

I got this set in for a picture problem. I bypassed the PIP and restored the pix but before doing this I noticed that the right channel audio was out. I initially concentrated on the PIP and after bypassing it and testing the set I noticed a humming sound from the right channel. The humming slowly increases in amplitude and after awhile it would occur in about one second bursts. The duty cycle, (for want of a better term) of these bursts eventually speeds up and after perhaps 30 more seconds short bursts of sound are then heard, (hum, sound, hum, sound, etc), until the sound stays on permanently. I found three caps in the audio circuit with somewhat high ESR and replaced them. Two were 100uf 10V and the third was a 22uf 50V. This however didn't seem to make much difference. There are two RCA outputs on the back of the set and they are both good. Has anyone seen this problem on one of these sets before? Thanks for any assistance. Lenny Stein, Barlen Electronics.

Reply to
captainvideo462002
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I know you mentioned the audio problem is in the right channel but maybe this tip will let you think outside the box, no pun intended.

From an old Mitsubishi tip file: Symptom: Int.distorted left audio.

Check for continuity of the grounding points on the heat sink of IC3A2 located on the main-pcb.

Good luck.

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David Farber
David Farber's Service Center
L.A., CA
Reply to
David Farber

Nothing weird about this one at all. It is very typical in this set. Start looking for more caps. You will find 1-2 dozen bad ones. Look in the 5 and

12 volt supplies, vertical circuit, power supply, etc.

Leonard

Reply to
Leonard Caillouet

Reply to
captainvideo462002

Grounding the input to the audio output chip eliminates the hum so I have chased the problem to an area before the output circuit but with the chassis up on end and very short wire lengths it gets very difficult at this point. Does anyone by chance have a schematic for this set? Thanks very much. Lenny.

Reply to
captainvideo462002

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