Troubleshooting Flow Charts; Shut Down - Toshiba TW40F80 Quick Reference Manual

UNIT POWERS UP
MOMENTARILY THEN
SHUTS DOWN
NO
THE PROBLEM MAY
Z801-16 GOES FROM
NOT BE A SHUTDOWN
HIGH TO LOW?
YES
MONITOR Z801-14.
NO
DOES VOLTAGE GO
ABOVE 1.5 V?
YES
ANODE OF D7701
NO
ABOVE APPROX.
ZERO VOLTS?
YES
ANODE OF D863
NO
ABOVE APPROX.
ZERO VOLTS?
YES
THE +30V SOURCE
IS TOO HIGH.
CHECK AND REPAIR.
Q768
Q759
COLLECTOR COLLECTOR
NO
ABOVE APPROX.
ABOVE APPROX.
ZERO VOLTS?
ZERO VOLTS?
YES
THE +30V SOURCE THE +15V SOURCE
HAS AN OVER HAS AN OVER
CURRENT CONDITION. CURRENT CONDITION.
CHECK AND REPAIR. CHECK AND REPAIR.
CONDITION.
ANODE OF D861
NO
ABOVE APPROX.
ZERO VOLTS?
YES
ANODE OF D866
ABOVE APPROX.
ZERO VOLTS?
THE +15V SOURCE
IS TOO HIGH.
YES
CHECK AND REPAIR.
THE +15V SOURCE
IS TOO LOW.
CHECK AND REPAIR.
Q762
NO COLLECTOR
BELOW APPROX.
ZERO VOLTS?
YES YES
THE -15V SOURCE
HAS AN OVER
CURRENT CONDITION.
CHECK AND REPAIR.
TROUBLESHOOTING
SHUTDOWN CIRCUITS
MONITOR Z801-13 .
NO
DOES VOLTAGE GO
ABOVE APPROX.
25 V?
YES
T-461 IS PRODUCING
EXCESSIVE HIGH
VOLTAGE. CHECK
AND REPAIR.
NO
ANODE OF D867
NO
ABOVE APPROX.
ZERO VOLTS?
ANODE OF D315
YES
ABOVE APPROX.
THE - 15V SOURCE ZERO VOLTS?
IS TOO LOW.
CHECK AND REPAIR.
THE +200V SOURCE
IS TOO LOW.
CHECK AND REPAIR.
*ALL VOLTAGES MUST BE MEASURED
WITH A PEAK RESPONSE METER.
VOLTAGE ACROSS R470
ABOVE 1.7V?
YES
THE +125V SOURCE
HAS AN OVER
CURRENT CONDITION.
CHECK AND REPAIR.
NO
YES
Q370 COLLECTOR
NO
ABOVE APPROX.
ZERO VOLTS?
YES
THE +35V SOURCE
HAS AN OVER
CURRENT CONDITION.
CHECK AND REPAIR.
JUNCTION OF
R888 AND R887
ABOVE 39V?
YES
THE +38V SOURCE
IS TOO HIGH.
CHECK AND REPAIR.