Agilent Technologies E3630A Manual De Funcionamiento Y Servicio página 93

Low output voltage 1. Measure voltage at the
(lower than rating) base of Q5.
2. Eliminate current limit
circuit as a source of
trouble by disconnecting
anode of CR11.
3. Measure voltage at pin
3 of U6.
SYMPTOM
The +20V supply must operate properly before troubleshooting the -20V supply.
High output voltage 1. Attempt to turn off Q8 by
(more than 1% shorting emitter-to-base
greater than +20V of Q8.
supply in fixed
tracking ratio mode) 2. Measure voltage at
base of Q7.
Low output voltage 1. Measure voltage at the
(more than 1% lower base of Q7.
than +20V supply in
fixed tracking ratio
mode)
2. Eliminate current limit
circuit as a source of
trouble by disconnecting
anode of CR18.
3. Measure voltage at pin
3 of U8.
Table A-5. +20V Supply Troubleshooting (Cont'd)
a. Measured voltage is less than 0
b. Measures voltage is more than 0
a. Output voltage increases.
b. Output voltage remains low.
a. Measured voltage is near
b. Measured voltage is zero volt.
c. Measured voltage is near
Table A-6. -20V Supply Troubleshooting
STEP - ACTION
a. Output voltage remains high.
b. Output voltage becomes near zero
a. Measured voltage is more than
b. Measured voltage is less than
a. Measured voltage is more than 0
b. Measured voltage is less than
0
a. Output voltage increases.
b. Output voltage remains low.
a. Measured voltage is near
b. Measured voltage is zero volt.
c. Measured voltage is near
volt.
volt.
-0.7V.
+0.7V.
RESPONSE
volt.
0 volt.
0 volt.
volt.
volt.
+0.7V.
-0.7V.
A-9
a. Check for open Q9, Q6, R26, or
CR5.
b. Proceed to step (2).
a. Check for U6B defective.
b. Reconnect lead and proceed to
step (3).
a. Check for defective U6A.
b. Check for CR14 or CR15 shorted.
c. Check for open R39, shorted R36,
or leaky or shorted C7.
PROBABLE CAUSE
a. Q8 shorted.
b. Remove short and proceed to
step (2).
a. Check for open CR20 or R14 and
check for defective U8A.
b. Check for defective Q7.
a. Check for open Q8, Q3, and R24.
b. Proceed to step (2).
a. Check for U8B defective.
b. Reconnect lead and proceed to
step (3).
a. Check for defective U8A.
b. Check for shorted CR21 and
CR22.
c. Check for open R15, shorted R41,
or leaky or shorted C6.