AWA (Mitsubishi) C4309 TV

Feb 18, 2007 3 Replies
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I'm troubleshooting an old AWA (Mitsubishi) C4309 TV that intermittently turns on by itself or changes channels randomly by itself. I've replaced about 10 dry electrolytics all over the chassis, but mainly in the standby PSU. I've also checked the electros around the uP and EEPROM. However the problem remains. I don't think it is a front panel issue as there is only one button to cycle through the channels, and this button selects the next preset in ascending order. Could a remote IR sensor cause a problem like this?


- Franc Zabkar


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R

Just had Hitachi with similar behaviour. IR sensor was at fault. Try disconnecting it and see what will happen. Power supplu to it may be "dirty" too.

Rudolf

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On Mon, 19 Feb 2007 10:30:50 +1100, "Rudolf" put finger to keyboard and composed:

Thanks for the feedback.

The problem did not recur after I disconnected the IR sensor module. I have now replaced three electros inside the module and the TV has been behaving ever since. Only one of the caps (a supply bypass cap) tested bad for ESR (11 ohms). However, I find this solution unconvincing as I had already replaced the caps in the PSU. BTW, I don't believe the problem was the result of IR interference, as the TV used to turn on by itself at night.

- Franc Zabkar

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Yes, caps in those old modules can cause lots of weird symptoms. I beleive you have fixed it.

Rudolf

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