Filter
Top Products
TM 11-6625-2958-14&P
Table 5-5. Series Regulator Troubleshooting, High Voltage Condition
STEP
ACTION
RESPONSE
PROBABLE CAUSE
in Table 5-4, Step 3.
1
These tests should be made with
Check turn-off of series
regulator transistors A4Q103
through A4Q108 by shorting
base (TP101) to emitter
(TP103).
external source connected as described
a. Output voltage remains high.
a. One or more of A4QI03
through A4Q108 shorted
or A4CR105 shorted.
Check A4R150-A4R155.
b. Output voltage decreases.
b. Remove short. Proceed
to Step 2.
2
Check turn-off of driver
A4Q102 by shorting base
(TP100) to emitter (TP101).
a. Output voltage remains high.
b. Output voltage decreases.
a. A4Q102 shorted.
b. Remove short. Proceed
to Step 3.
3
Check conduction of error
amplifierA4Q101 by connect-
ing base (TP45) to cathode
of CR45 (TP67) through a
100
Ω
resistor.
a. Output voltage remains high.
b. Output voltage decreases.
a. A4Q101 open.
b. Remove resistor. Pro-
ceed to Step 4.
Check conduction of error
amplifier Q42 by connecting
base (TP44) to cathode of
CR45 (TP67) through a 1K
Ω
resistor.
a. Output voltage remains high,
b. Output voltage decreases.
a. Q42 open.
b. Remove resistor. Pro-
ceed to Step S.
4
s Check turn-off of mixer am-
plifier Q41 by connecting
base (TP40) to +11 volt sup-
ply (TP66) through a 1K
Ω
resistor.
a. Output voltage remains high.
b. Output voltage decreases.
a. Q41 shorted.
b. Remove resistor. Pro-
ceed to Step 6.
6 Check turn-off of constant
voltage comparator Z 1 by
shunting R 1 with a 10K
Ω re-
sistor, or by installing a
10K
Ω resistor in R1 position
if resistor is not installed
in the supply.
a. Qutput voltage remains high.
b. Output voltage decreases.
a. Z1 defective, R110
shorted.
b. R23 open, open strap
between A 1 and A2,
A5R121 or A5R122 open.
Table 5-6. Series ReguIator Troubleshooting, Low Voltage Condition
1
STEP
ACTION
RESPONSE
PROBABLE CAUSE
These tests should be made with external source connected as described in Table 5-4, Step 3.
1
A4Q103 throughA4Q108
open and/or A4R150
through A4R155 open,
Check conduction of series
regulator transistors A4Q103
through A4Q108 by connect-
ing base (TP101) to +11 volt
supply (TP66) through a 100
ohm resistor.
a. Output voltage remains low.
b. Output voltage rises.
a.
b.
A4CR106 shorted.
Remove resistor. Pro-
ceed to Step 2.
I
5-13