TM 55-4920-390-13&P
Table 6-1. Troubleshooting Check Chart, continued.
Item
Trouble
Probable Cause
Corrective Action
4.
Failure of
Lack of locking
Turn Gain pot CW.
oscillator to lock.
signal.
Check that gap between
No one-per-rev
magnetic pickup and wiper
flash with "vernier"
is approximately .020" to
CCW.
.040" (thickness of match-
book cover). Make certain
pickup is good. Check conn
connector and cable.
Remember rotor head must
be turning to generate
signal.
6-3. TEST PROCEDURES. To test the Strobex, proceed as follows -
Test equipment required:
a) Voltohmmeter (multimeter) Simpson 260 or equal.
b) Signal generator (sine wave or pulse).
c) DC power source - 28 VDC at 5 amps.
d) OsciIloscope - Tektronix 503 or equal.
NOTE
Great care has been taken to make all test points available WITHOUT REMOVING CIRCUIT BOARD.
Remove circuit compartment cover by removing the five screws holding it and sliding it out. DO
NOT LOOSEN or REMOVE CIRCUIT BOARD, and DO NOT UNWIRE ANYTHING unless fault is
located by the following tests. ONLY THEN remove (loosen) circuit board (as in 5-7, a thru d) and
repair or replace parts as required.
NOTE
Test points 1 thru 6 appear as numbers on circuit board and on Circuit Diagram (Fig. 1-8) and
Circuit Board Assembly Drawing (Fig. 9-4). Test points A, B, C and D show on Circuit Diagram
6-3
