ARMY TM 5-6675-238-14
MARINE CORPS TM 08839A-14/1
Legend for figure 8-10 - Continued
106.
107.
108.
109.
110.
111.
112.
113.
114.
Lockwasher
Washer
Rectifier CR1
Voltage regulator A7
clamp
Capacitor C1
Screw
Lockwasher
Terminal lug
115.
116.
117.
118.
119.
120.
121.
122.
123.
Screw
Washer
LockWasher
Nut
Resistor R4
Rectifier CR2
Screw
Capacitor
Transistor Q1
(1)
(2)
(3)
(4)
Open lamp assembly cover (5).
Remove two screws (6) and washers (7) secur-
ing lamp support (12); allow lamp support to
hang loosely.
Identify and unsolder each photocell small
color-coded wire from terminal board TB2
(89, figure 8-10, sheet 2) terminals 1 thru 10.
Remove two screws (13, figure 8-10, sheet 1)
securing photocell assembly (2) to lamp sup-
port; remove photocell assembly,
b. Replacement.
(1)
(2)
(3)
(4)
(5)
Carefully install photocell assembly (4) on
lamp support (12) and secure with two screws
(13).
Identify and solder each photocell color-coded
wire to terminal board TB2 (89, figure 8-10,
sheet 2). See tape reader schematic diagram
(figure FO-19) for location of each color-coded
wire on terminal board TB2.
Secure lamp support (12, figure 8-10, sheet 1)
with two screws (6) and washers (7). Visually
align lamps with photocell assembly, Position
lamp support so that clearance from lamp
assembly to photocell assembly is 0.035 to
0.045 inch.
Close lamp assembly cover (5).
Perform photocell amplifier A1 bias adjust-
ments in accordance with procedure in table
8-8, test 5.3.
8-28. Plug-In Circuit Card A1, A2, A3, A4, A5, A6, or
A7 Removal and Replacement. See figure 8-10, sheet 2,
and remove and replace photocell amplifier Al (57) as
follows:
a. Removal Carefully pull photocell amplifier A1
(57) out of the card cage using handle on top of
photocell amplifier A1.
When installing a plug-in circuit card,
check that it is the proper card for the
respective receptacle. Check that the card
is properly aligned during installation or
damage to connector or receptacle may
result.
b. Replacement. Install photocell amplifier A1 (57)
in card guides and slide inward to engage connector.
8-29. Servo Feedback Potentiometer R2 or R3 Re-
moval and Replacement. See figure 8-10, sheet 2, and
remove and replace servo feedback potentiometer R2
(65) as follows:
a. Removal.
(1) Tag and unsolder wires from servo feedback
potentiometer R2 (65).
(2) Loosen two setscrews securing servo feedback
potentiometer R2 shaft to sensing arm drum
assembly.
(3) Remove three screws (66), washers (68), lock-
washers (67), and clamps (69) securing servo
feedback potentiometer R2 (65) to bracket
support; remove potentiometer R2.
b. Replacement.
(1)
(2)
(3)
(4)
Secure servo feedback potentiometer R2 (65)
to bracket support with three screws (66),
washers (68), lockwashers (67), and clamps
(69). Align position of potentiometer for free
movement of bearings allowing tape sensing
arm to swing parallel to the front panel.
Tighten two setscrews securing servo feedback
potentiometer R2 shaft to sensing arm drum
assembly.
Solder wires to potentiometer.
Adjust servo feedback potentiometer R2 in
accordance with procedure in table 8-8, test 3.
8-101
