14
4. Power supply
MG5.1E
Personal notes
To troubleshoot the Standby Supply, first check the supply
voltage on Pin 5 of 7211. If there is no secondary voltage and
7211 is working correctly, startup pulses should be seen at Pin
5 of the IC. If the IC is pulsing and there is no secondary
voltage, there is a problem with the outputs of 5202 or with the
feedback circuit. If 7211 is not pulsing, either the IC or capacitor
2283 is defective.
When the set is turned On, transistor 7214 will turn Off turning
7205 On. This will turn the Optoisolator 7206 On turning
transistor 7204 On, switching the operating voltage to the
Power Factor Correction circuit. It also switches the operating
voltage to the power supply on the Audio Amplifier panel on the
line labeled "CONTROL".