The Full Power supply produces two 130 volt, a 35 volt, a 22 volt, a minus 22 volt, a minus 35 volt, a
plus audio supply, and a minus audio supply. The Audio supply is a plus and minus 19 volts in sets
that use the 20-watt audio amplifier. The Audio supply voltages will be four volts higher in sets with a
30-watt audio amplifier.
When troubleshooting, notice that the Hot ground for the Full power supply is separated from the main
Hot ground on the Input Panel by Choke 5330. To ensure correct readings, use the Hot ground in the
Full power supply. If the power supply is overloaded or the operating voltage is missing, the voltage
on Pin 1 of the IC will be changing between 9.4 and 14.5 volts. Each time the voltage reaches 14.5
volts, drive will appear on Pin 3 of the IC. If a voltage is present on Pin 1 that is greater than 14.5
volts, and there is no drive on Pin 3, the IC should be replaced. If drive is present on Pin 3, check for
drive on the Drain of 7301. If drive is present here, check for a short on the 130-volt lines, a problem
in the feedback circuit, or a problem with the operating voltage.
Power Fail Shutdown
Figure 6