Fault Isolation Tests

TM 11-6130-392-34

a. Check Panel Meter.

k. With positive lead of multimeter, measure

voltage at pins 2, 3, 4, 13, 22 and 26 of A12 timing

(1) If meter shows current reading; go to step

circuit assembly.

(2) If no current reading on meter; go to step e.

(1) If the meter reading is less than 1 volt for

b. Set POWER to OFF. Refer to paragraph 3-9b.

each pin, set POWER switch to OFF and replace

A12 (Section IV, para. 3-16).

and put A12 (fig. 3-2) on extender board.

c. Set multimeter to 10 VDC scale. Connect nega-

(2) If the meter reading is 1 volt or more for

tive meter lead to negative () terminal of filter

any pin; discontinue testing, send battery charger

capacitor C1 (fig. 3-3). Connect positive (+) lead to

to next higher maintenance level. Go to section V.

l. Set POWER switch to OFF. Remove all display

A12-TP2 (fig. 3-6). Set POWER to ON.

modules. Be sure to remember which module goes

(1) If the meter reading is 7.0 volts or more; go

to step d.

into each socket. Refer to section IV, paragraph

3-17 for disassembly instructions.

(2) If the meter reading is less than 7.0 volts;

m. Refer to paragraph 3-9b. and put A12 timing

discontinue testing, send battery charger to next

higher maintenance level.

circuit assembly (fig. 3-6) on extender board.

d. Remove positive lead of multimeter from

n. Using multimeter, check continuity between

each pin of each display module socket and the ap-

A12-TP2 and connect to S3-TP1 (fig. 3-3).

propriate pin on A12. Refer to table 3-4 and figure

(1) If meter reading is less than 7.0 volts; dis-

3-7.

c o n t i n u e testing, s e n d b a t t e r y c h a r g e r t o n e x t

higher maintenance level.

(1) If continuity is good for every pin, go to

step o.

(2) If meter reading is 7.0 volts or more; set

POWER to OFF, replace A12 (Section IV, para 3-

(2) If continuity is not good for all of the pins;

16), go to section V.

discontinue testing, send battery charger to next

e. Set POWER to OFF. Remove F6 fuse (fig. 2-2);

higher maintenance level.

check continuity with multimeter.

o. Insert display modules into their original

sockets.

(1) If F6 is good; go to step f.

(2) If F6 is faulty; go to step m .

p. Remove and interchange any two of the dis-

f. Refer to paragraph 3-9b. and put A11 power

play modules.

supply assembly (fig. 3-2) on extender board. Insert

q. Set POWER switch ON. Press START TIME

F6 fuse and screw-on cap.

switch.

g. Set POWER to ON. Set multimeter to 50 VAC

(1) If display reads exactly the same as in step

scale. Measure A11 (fig. 3-4) AC volts between pins

a; go to step r.

A11-22 and A11-23 on extender board.

(2) If display does not read exactly the same as

in step a; set POWER switch to OFF. Replace all

(1) If meter reading is 7.0 volts or more; go to

step h.

display modules and reassemble display circuit as-

(2) If meter reading is less than 7.0 volts; dis-

sembly A13 (Section IV, para 3-17). Go to section V.

continue testing, send battery charger to next high-

r. Set multimeter to 10 VDC scale. Connect nega-

er maintenance level.

tive lead to negative () lead of C1 (fig. 3-3). With

h. Set multimeter to 10 VDC scale. Connect mul-

positive (+) lead of multimeter, measure voltages at

timeter negative lead to negative () lead of C1 (fig.

pins 1, 27, and 28 of A12 timing circuit assembly (fig.

3-3). Connect the positive lead to A11-TP3 (fig.

3-6).

3-4).

(1) If meter reading is 9.0 volts or greater for

(1) If meter reading is 7.0 volts or more; go to

each pin measured, go to steps.

step i.

(2) If meter reading is less than 9.0 volts for

any pin measured, discontinue testing, send battery

(2) If meter reading is less than 7.0 volts; set

POWER to OFF, and replace A11 (Section IV, para

charger to next higher maintenance level.

s. With positive lead of multimeter, measure

3-15). Go to section V.

voltage at pins 2, 3, 4, 13, 22 and 26 of A12 timing

i. Set POWER switch to OFF. Remove positive

lead of multimeter from A11-TP3. Remove A11 and

circuit assembly.

the extender board and return All into its original

(1) If the meter reading is less than 1 volt for

location. Refer to paragraph 3-9b. and put A12 (fig.

each pin, set POWER switch to OFF and replace

A12 (Section IV, para 3-16). Go to section V.

3-2) on extender board.

j. Set POWER switch ON. Connect positive lead

(2) If the meter reading is 1 volt or more for

of multimeter to A12 (fig. 3-6) by using pin 41 on ex-

any pin; discontinue testing, send battery charger

to next higher maintenance level.

tender board.

Test 6. 10 Volt Power Supply Test.

(1) If meter reading is 7.0 volts or more; go to

3-12