jak
New User
Jan 1, 2004, 6:33 PM
Post #1 of 1
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Hello fellow tv repair technicians. my name is Joe and i have a PSU, problem (I think) in a Sony CTV Model KV21 XMU.
When the tv is switched on you can hear the 'groan' of the current into the degaussing coils, closely followed by the 'thwack' of the EHT; then nothing. On first inspection i noticed that R 614 (220R) had carbonised round one of its legs. i repaired that but symptoms remained the same.
I disabled the line o/p stage by disconnecting the line o/p transistor and putting a 60 watt bulb across C621, to monitor the PSU o/p voltage. I
Initially the bulb brightened up and the o/p voltage measure 147V+; in a few seconds it had fallen to around 90V+, correspondingly the bulb dimmed and shortly after, went out.
Switching the tv on and off again immediately produced NO o/p volts from the PSU, however. Leaving the set switched off for about 2-minutes and then switching it on again allowed the PSU to 'perform' for another few seconds and then go dead.
I don't have a circuit diagram to delve further but would appreciate any advice/help. Thank You
Yours Joe
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