TM 11-6625-2958-14&P

 

 

 

 

Table 5-5.Series Regulator Troubleshooting, High Voltage Condition

 

 

 

 

 

 

 

 

STEP

 

 

ACTION

 

RESPONSE

 

PROBABLE CAUSE

 

 

 

 

 

 

 

These tests should be made with

external source connected as described

in

Table 5-4,Step 3.

1

 

Check

turn-off of series

a. Output

voltage

remains high.

a. One or more of A4QI03

 

 

regulator transistors A4Q103

 

 

 

 

through A4Q108 shorted

 

 

through A4Q108 by shorting

 

 

 

 

or A4CR105 shorted.

 

 

base (TP101) to emitter

 

 

 

 

Check A4R150-A4R155.

 

 

(TP103).

b. Output

voltage

decreases.

b. Remove short. Proceed

 

 

 

 

 

 

 

 

 

 

 

 

 

 

to Step 2.

 

 

 

 

 

 

 

 

2

 

Check

turn-off of driver

a. Output

voltage

remains high.

a. A4Q102 shorted.

 

 

A4Q102 by shorting base

b. Output

voltage

decreases.

b. Remove short. Proceed

 

 

(TP100) to emitter (TP101).

 

 

 

 

 

 

to Step 3.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3

 

Check conduction of error

a. Output

voltage

remains high.

a. A4Q101 open.

 

 

amplifierA4Q101 by connect-

b. Output

voltage

decreases.

b. Remove resistor. Pro-

 

 

ing base (TP45) to cathode

 

 

 

 

 

 

ceed to Step 4.

 

 

of CR45 (TP67) through a

 

 

 

 

 

 

 

 

 

 

 

 

 

100 Ω resistor.

 

 

 

 

 

 

 

 

 

 

 

 

 

4

 

Check conduction of error

a. Output

voltage

remains high,

a.

Q42 open.

 

 

amplifier Q42 by connecting

b. Output

voltage

decreases.

b. Remove resistor. Pro-

 

 

base (TP44) to cathode of

 

 

 

 

 

 

ceed to Step S.

 

 

CR45 (TP67) through a 1K Ω

 

 

 

 

 

 

 

 

 

 

 

 

 

resistor.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

s

 

Check

turn-off of mixer am-

a. Output

voltage

remains high.

a.

Q41 shorted.

 

 

plifier

Q41 by connecting

b. Output

voltage

decreases.

b.

Remove resistor. Pro-

 

 

base (TP40) to +11 volt sup-

 

 

 

 

 

 

ceed to Step 6.

 

 

ply (TP66) through a 1K Ω

 

 

 

 

 

 

 

 

 

 

 

 

 

resistor.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

6

 

Check

turn-off of constant

a. Qutput

voltage

remains high.

a.

Z1 defective, R110

 

 

voltage comparator Z 1 by

 

 

 

 

shorted.

 

 

shunting R 1 with a 10K Ω re-

b. Output

voltage

decreases.

b. R23 open, open strap

 

 

sistor,

or by installing a

 

 

 

 

 

 

between A 1 and A2,

 

 

10K Ω resistor in R1 position

 

 

 

 

 

 

 

 

 

 

A5R121 or A5R122 open.

 

 

if

resistor is not installed

 

 

 

 

 

 

 

 

 

 

 

 

 

in

the

supply.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Table 5-6.Series ReguIator Troubleshooting, Low Voltage Condition

STEP

ACTION

RESPONSE

PROBABLE CAUSE

 

 

 

 

 

 

 

 

These tests should be made with external source connected as described in Table 5-4,Step 3.

1

1Check 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. a. A4Q103 throughA4Q108 open and/or A4R150 through A4R155 open, A4CR106 shorted.

b. Output voltage rises.

b. Remove resistor. Pro-

 

ceed to Step 2.

I