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SERVICE HINTS
POWER FAILURE DETECTOR
This unit is equipped with a Power Failure Detector function included in the CPU which checks for an abnormal condition in
the chassis power supplies, including the power supply derived from the Horizontal Output Transformer.
If, while the power is on, a failure is caused by any of the following that results in a low voltage supply, the CPU will turn the
unit off in 1.5 seconds to prevent further damage:
•
Failure within the power supply circuits.
•
A short circuit in the load side from the supply.
•
Stoppage of the Horizontal Output Oscillator caused by the X-Radiation protection Hold-Down Circuit.
If, while the power is off, the power is switched on and any of these failures remains uncorrected, the CPU will shut off the
power within three seconds.
Check the following if the unit is turned off by the power failure detector.
1. Disconnect the AC power cord (120V AC line) for at least 10 seconds.
2. Connect a DC Voltmeter to the following TEST POINTS.
3. Press the Power key and check for the proper voltage supplies.
4. If any of these voltages is low, the power failure detector should turn the unit off within three seconds.
5. Check all circuits listed above.
Note: This unit is equipped with a Power Surge Protection feature included in the CPU. If power failure occurs three times
within 15 minutes, the CPU will automatically stop functioning to help prevent secondary damage. (TV will not turn
on by pressing the power key.) To reset the operating programs within the CPU, disconnect the AC power cord for
at least 10 seconds.
D508
26V
TJ6
5V
D429 Cathode
8V
D643
12V
