Recently, I received a Sony PVM-9045 which would not start up.
After some time, I found the Horizontal oscillator frequency on Pin 5 of the uPC1377C sync IC was about 365kHz, way above the normal 15-16kHz range and therefore preventing any output on Pin 10 of the uPC1377C.
Further investigation revealed that C517, a 0.0056uF polypropelyene unit was defective (it was the timing capacitor for the Horizontal oscillator) and replacing it restored operation.
Notably, the defective unit had a significant cosmetic defect, even though it was within tolerance when measured with a capacitance meter out of circuit, which means this capacitor could have been leaky.
After some time, I found the Horizontal oscillator frequency on Pin 5 of the uPC1377C sync IC was about 365kHz, way above the normal 15-16kHz range and therefore preventing any output on Pin 10 of the uPC1377C.
Further investigation revealed that C517, a 0.0056uF polypropelyene unit was defective (it was the timing capacitor for the Horizontal oscillator) and replacing it restored operation.
Notably, the defective unit had a significant cosmetic defect, even though it was within tolerance when measured with a capacitance meter out of circuit, which means this capacitor could have been leaky.
