No power supply, light is not bright can have several reasons: JVKservice manual download site
JVKservice manual download site
1. The power supply circuit fault JVKservice manual download site
JVKservice manual download site
2. The CPU control part of failure JVKservice manual download site
JVKservice manual download site
3. Load short circuit inspection process: JVKservice manual download site
JVKservice manual download site
Boot testing power supply, found STB5V no output, detection D501 300 v output, no control voltage detection STB5V power IC501 fourth foot, IC501 fourth foot control voltage is provided by MC501 7 feet and measuring MC501 7 feet without output, doubt IC501 4 feet short circuit, suck empty MC501 7 feet, found that the output voltage control, the problem should be in IC501 or peripheral circuit. Detect IC501 element around 4 feet, find ZD503 breakdown voltage regulator tube, replacing ZD503 of commissioning to normal.JVKservice manual download site
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