Service manual

32 Troubleshooting
NO
YES
START
"NO DISPLAY"
TURN OFF SUPPLY, REMOVE TOP COVER AND RFI
SHIELD. UNPLUG CABLE W5 FROM J108 ON A2 GPIB
YES
NO
PROBABLE DEFECTIVE A1 BOARD
YES
NO
YES
NO
LCD DSP1 OR CABLE W2 IS DEFECTIVE.
WARNING:
THS CONFIGURATION IS FOR THE TEST ONLY. DO NOT
FLOAT THE OUTPUT OR ATTEMPT TO OPERATE THE SUPPLY.
BOARD AND UNPLUG CABLE W4 FROM J507 ON A10
CONTROL BOARD. PLUG CABLE W5 INTO J507 ON
A10 BOARD. THIS REMOVES GPIB BOARD FROM THE
DATA PATH AND CONNECTS THE FRONT PANEL
DIRECTLY TO THE CONTROL BOARD, SEE WARNING.
TURN ON THE SUPPLY AND TRY TO PROGRAM THE
SUPPLY FROM THE FRONT PANEL.
SUPPLY
OPERATES
PROPERLY?
CHECK TEST POINTS 1 - 4 . (SEE TABLE 6-3).
CHECK CABLE W4.
TURN OFF THE SUPPLY IN ORDER TO ACCESS
A1 FRONT PANEL BOARD. REMOVE A1 FRONT
PANEL ASSEMBLY.
TURN ON SUPPLY. CHECK +5V BIAS AT R1-6
CONNECT METER COMMON TO R1-3.
CHECK THE FOLLOWING DISPLAY VOLTAGES:
1.1V AT R1-14; 2.2V AT R1-2.
DISPLAY
& BIAS VOLTAGES
OK?
CHECK 12 MHz CLOCK SIGNAL AT A1U3-66.
IS
12MHz
SIGNAL OK?
CONNECT EXTERNAL VOLTMETER TO OUTPUT
TERMINALS. PROGRAM VOLTAGE AND CURRENT
IS
OUTPUT VOLTAGE
PRESENT?
AT THE FRONT PANEL. MEASURE VOLTAGE AT
OUTPUT TERMINALS. (IF OUTPUT IS DISABLED,
PRESS OUTPUT KEY).
YES
NO
CHECK
PCLR (RESET*)
A2U2-16 = 5V?
OR A2 BOARD
PROBABLE DEFECTIVE A1 BOARD
PROBABLE DEFECTIVE A1 BOARD
PROBABLE DEFECTIVE A1 BOARD
PROBABLE DEFECTIVE A6 BOARD.
Figure 3-2. No Display Troubleshooting)