B-62
ARMY TM 5-6675-238-14
MARINE CORPS TM 08839A-14/1
Table 8-7. FAILURE/ACTION Indicator Number Definition
FAILURE/
ACTION number
Definition
Action
NOTE
For any number other than those listed below, first check cable connections as per figure 8-2. If still fails, replace
A3, then A1, and then A2.
00
Action indication
Requires operator to turn off SPU SELF TEST switch-
indicator
20
SPU + 15V failure
Check + 15V. If not present, replace +15 VDC fuse,
PS3, and/or Z3. If still failure, replace A3
21
SPU -15V failure
Check -15V. If not present, replace -15 VDC fuse,
PS4, and/or Z4. If still failure, replace A3
28
SPU + 15V failure
Check + 15V. If not present, replace +15 VDC fuse,
PS3, and/or Z3. If still failure, replace A3
29
SPU -15V failure
Check -15V. If not present, replace -15 VDC fuse,
PS4, and/or Z4. If still failure, replace A3
30
SPU time-out-counter (TOC) failure
Replace A1; if still failure, replace A3; then check tape
reader as per paragraph 8-10 and table 8-8 (lamps,
photocells, and amplifier A1 have highest probability
of being the problem areas)
NOTE
When TOC failure occurs, turn power off and rerun tests.
32
38
40
41
46
SPU comparator, execute, reverse,
or load function failure. SPU tele-
typewriter control circuitry failure
SPU time-out-counter failure
Action indication
Cables improperly connected
Action indication
Check that the cables to the SPU are connected as
per figure 8-2. Special emphasis should be given to
insure that cable W209 is connected properly and
that cable W212 is not connected during the first
part of the SPU self-test procedure. Also, be certain
that power to the SPU was cycled off via the SPU
ON switch-indicator at least once prior to the start
of the SPU self-test procedure. If this was not per-
formed, then reverse the self-test tape to the begin-
ning of self-test and cycle SPU power via the SPU
ON switch-indicator before performing self-test
again. If still fails, replace A1, then A3, and then A2
Replace A3; if still failure, replace A1, then A2
Requires operator to connect TTY and buffer unit and
to check that the EXECUTE indicator is on. If
indicator is not on, replace buffer unit, If still not on,
replace A1, then A3
Remove cables W205 and W210 from the SPU (the
buffer unit is not to be connected during the first part
of self-test)
Requires operator to check that EXECUTE switch-
indicator is out. If EXECUTE switch-indicator is not
out, replace A1, then A3. If TTY echo-back does not
work properly, replace TTY. If still a failure, replace
A1
