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
4.4n. Test results
All test steps (4.4d through 4.4l) had
normal indications:
Replace B1 if
stepping motor does not drive
All test steps (4.4d thru 4.4) failed: Re-
place A3. If all tests still fail, replace
A4 and A5
Test steps 4.4g and 4.4h both passed but
4.4k and 4.4l both failed, or vice
versa: Replace A3
Test step 4.4d passed but 4.4e failed or
vice versa: Replace A4
Test step 4.4g passed but 4.4h failed or
vice versa: Replace A5
Any combination of failures not listed
above: Replace B1. If still fails, re-
place A3
4.4o. Reinstall A4 and A5 in
proper card cage positions
5. TIMING CALIBRATION.
5.1 STEP RATE CALIBRATION
(Run mode).
5.1a. Connect 10:1 probe to oscil-
loscope channel A input
5.1b. Connect oscilloscope than- Oscilloscope displays
nel A probe ground return
shown in figure 8-5
to ground (TB2 terminal 10,
TP5) and connect same
probe to pin 1 of card A2.
Use card extender. Verify
that SPU REVERSE switch-
indicator is on (switch-indi-
cator must be lighted)
5.1c. Remove A2 from card ex-
tender and reinstall in card cage
5.2. STEPPING
MOTOR
ALIGNMENT.
waveform A
5.2a. Press SPU REVERSE or SPU REVERSE switch-indicator
MEMORY LOAD switch-in-
light goes off
dicator to off (if on). Set
SPOOLING switch to EN-
ABLE position
Voltage out of tolerance: Perform test 4
Period T2 out of tolerance: Alternately
adjust A2R5 and A2R6 until the pe-
riod is correct. If it will not adjust to
proper tolerance, then perform test 4
Period T1 out of tolerance: Replace A2
NOTE
If this test was performed as a part of
step 4.2g, return to step 4.2g
Refer to table 8-6
8-73
