(21)
(22)
(23)
(24)
(25)
(26)
(27)
(28)
(29)
(30)
(31)
(32)
(33)
(34)
(35)
(36)
(37)
(38)
(39)
(40)
Press SELF TEST switch-indicator to on,
Tape will advance and FAILURE/ACTION
indicator displays 58.
Verify that
DVM indicates -7.495 to
-7.505V. If out of tolerance, replace A2.
Press SELF TEST switch-indicator to off.
Repeat steps. h(9) through h(23) to adjust for
any interaction between adjustments. The tape
contains the same information a second time.
Connect DVM positive test lead to A2TP-2.
Press SELF TEST switch-indicator to on.
Tape will advance and FAILURE/ACTION
indicator displays 42.
Verify that DVM indicates -9.975 to
-9.985V. If not, adjust resistor A2R18.
Press SELF TEST switch-indicator to off.
Press SELF TEST switch-indicator to on.
Tape will advance and FAILURE/ACTION
indicator displays 44.
Verify that DVM indicates -4.975 to
-4.985V. If not, adjust resistor A2R4.
Press SELF TEST switch-indicator to off.
Press SELF TEST switch-indicator to on.
Tape will advance and FAILURE/ACTION
indicator displays 46.
Verify that DVM indicates +4.975 to
+ 4.985V. If not, adjust resistor A2R17.
Press SELF TEST switch-indicator to off,
Press SELF TEST switch-indicator to on.
Tape will advance and FAILURE/ACTION
indicator displays 48.
Verify that
DVM indicates + 9.975 to
+ 9.985V. If not, adjust resistor A2R16.
Press SELF TEST switch-indicator to off.
Disconnect DVM.
Press REVERSE switch-indicator to rewind
tape.
Perform self-test procedure in accordance
with paragraph 8-9.
8-24. Tape Reader, Part No. 877406-1, Maintenance.
Tape reader maintenance consists of removal and re-
placement of the lamp assembly, photocell assembly,
instrument case, plug-in circuit cards, front panel com-
ponents, and chassis components. All removal and re-
placement procedures (except lamp assembly) require
removal and replacement of the instrument case which
is described, once only, in paragraph 8-26. Where
similar components are removed and replaced by identi-
cal procedures, one typical procedure will be given. If
ARMY TM 5-6675-238-14
MARINE CORPS TM 08839A-14/1
applicable, tag and unsolder, or disconnect, wires prior
to removing components. Before performing any main-
tenance, the tape reels should be removed from the
tape reader. In addition, cleaning of the tape reader
head and tapes is included.
8-25. Lamp Assembly DS1 Removal and Replacement.
See figure 8-10, sheet 1, and remove and replace lamp
assembly DS1 (10) as follows:
a. Removal.
(1) Open lamp assembly cover (5).
(2) Remove two screws (11) securing lamp assem-
bly (10) to lamp support (12).
(3) Carefully raise lamp assembly up and away
from lamp support. When lamps are clear of
retaining slots, withdraw lamp assembly until
soldered wire ends are accessible.
(4) Tag and unsolder wires from lamp assembly;
remove lamp assembly.
b. Replacement.
(1) Solder wires to lamp assembly.
(2) Carefully guide lamp assembly (10) lamps into
retaining slots and onto lamp support (12).
To avoid stripping threads, do not over-
tighten plastic screws.
(3) Secure lam assembly to lamp support with
two screws (11).
(4) Close lamp assembly cover (5).
8-26. Instrument Case Removal and Replacement. See
figure 8-10, sheet 1, and remove and replace instrument
case (3) as follows:
a. Removal. Press pressure relief valve; then re-
move 20 screws (1) and washers (2) securing tape reader
to instrument case (3). Remove tape reader from instru-
ment case.
b. Replacement. Install tape reader in instrument
case (3) and secure with 20 screws (1) and washers (2).
8-27. Photocell Assembly CR3 Removal and Replace-
ment. See figure 8-10, sheet 1, and remove and replace
photocell assembly CR3 (4) as follows:
a.
Do not attempt to repair or resolder
wires at the photocell. If damage occurs,
replace entire photocell assembly.
Removal.
Change 1
8-97
