ARMY TM 5-6675-238-14
MARINE CORPS TM 08839A-14/1
Table 8-8. Tape Reader Testing and Troubleshooting Procedure - Continued
Malfunction indication/
Test procedure
Normal indication
corrective action
5.2b.
Voltage out of tolerance: If voltage is
+ 1.0 to + 3.0V, redate A1. If still
5.2c.
5.2d.
5.2e.
Connect DVM negative test
lead to ground (TB2 termi-
nal 10; TP5) and positive
test lead to A1 card cage pin
M. (Install A1 in card ex-
tender)
DVM indicates +3.0 to + 5.5V
Set SPOOLING switch to
DISABLE position
Install SPU Self-test tape on
tape reader in any area of
the tape
that contains
sprocket holes. Also, install
take-up reel
Set SPOOLING switch to
ENABLE (if not already set)
Stepping motor is extremely hot to
the touch.
5.2f. Loosen three clampdown
screws on stepping motor B1
(two access holes alongside
Q1 are provided for this pur-
pose) and slowly turn B1
clockwise (not more than
1/10 turn). Then, turn coun-
terclockwise until the DVM
indicates less than + 0.5V in
each direction. Center B1 be-
tween the two extremes
5.3. PHOTOCELL AMPLIFIER
ADJUSTMENT.
DS1 tape reader head lamps go off
and DVM indicates less than
+ 0.5V
DVM indicates (for sprocket hole)
+3.0 to + 5.5V then indicates O
to 0.5V for each extreme (clock-
wise and counterclockwise) and
finally indicates +3.0 to + 5.5V.
fails, replace SPU board A1. If voltage
is less than + 1.0V, adjust A1R3 coun-
terclockwise (no more than 10 turns)
until the voltage is in tolerance and
then make one more complete turn, If
voltage is still out of tolerance, re-
place A1
Lamps fail to go off: Replace S1
Voltage out of tolerance: Return to
step 5.1a and continue. If this fails,
replace A1
5.3a. With SPU self-test tape in-
stalled on the tape reader,
advance tape to area that
contains all holes (toward
end of tape, after SPU self-
test and immediately before
SPU calibration)
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