Service manual

36 Troubleshooting
START
"OUTPUT HELD HIGH"
TURN OFF THE SUPPLY AND REMOVE THE
COVER AND RFI SHIELD. DISCONNECT LOAD.
TURN SUPPLY ON AND CHECK THE BIAS AND
REFERENCE VOLTAGES (TEST POINTS 9
THROUGH 22 . SEE TABLE 6-3.
NO
YES
ARE
VOLTAGES
OK?
DISABLE THE OV CIRCUIT BY LIFTING
A10R536. TURN ON SUPPLY AND PROGRAM
OUTPUT VOLTAGE AND CURRENT TO ZERO.
CHECK IF CV "OR" GATE DIODE
A10D652 IS CONDUCTING
A10D652
CONDUCTING?
NO
YES
CHECK VOLTAGE LEVEL AT FAST SENSE
DIFF AMP A10U608-7 49 .
DOES
TP 49
= -10V?
NO
YES
PROBABLE DEFECTIVE A6 BOARD
PROBABLE DEFECTIVE A10 BOARD
PROBABLE DEFECTIVE A10 BOARD
PROBABLE DEFECTIVE A10 BOARD
OR A8 FAST SENSE BOARD
Figure 3-6. Output Held High Troubleshooting)