Friday, February 3, 2017

China TV (La76931) No raster, picture or sound

Clifford May Johannesburg South Africa
Hi Humphrey,
I've got a problem with this TV as you will see on the schematic I've got all voltage except 5volt on n552. 12v is ok on n551 but no 5volt coming out of n552. It gives me 1.2volt. I also changed transistor n552 but still the same. I desperately need your help please. Thanks in advance.
Kind Regards
Clifford





Sounds like there is something shorted after this i.c (N552). Follow this 5 volts out and see what it feeds, this include jungle i.c la 76931, very suspect.

Solder out pin 43 of the La76931 out of circuit and see if the voltage now go up to 5 volts, if it goes up means the ic is shorted, also see if this ic is getting very hot(la76931) could also means it is bad,

Next solder out pin 55 of the La76931 out of circuit and see if the voltage now go up to 5volts

See attached for more info...


Hi Humphrey,
Thank you sir, I found out that it was indeed the I.C la 76931 that was bad. Changed it and boom the set went on.
Thanks a million
Regards

Clifford May

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