b. General test procedures.
You must determine the type of test and
the location of the test points to identify the actual bad item of
equipment.
Troubleshooting techniques for these types of defects are
circuit substitution, followed by continuity measurements.
c. Test procedure 83. With no sidetone, move the handset to the KY-57
audio connector. (Figure 104)
Remove the CX-13062 from the KY-57 audio connector and connect
the handset to the audio connector.
Key and speak into the mike.
If no sidetone is heard, the KY-57 is bad.
If sidetone is heard, remove the RT from the MT-1029.
Remove the CX-13062/U from the J-3513/U J1.
Measure continuity on the CX-13062/U P1 pin D to P2 pin D.
If the measurement is infinity, the CX-13062/U is bad (open).
If zero ohms, measure continuity on the CX-13062/U at P1 or P2
pin A to pin D.
If zero ohms is measured, the CX-13062/U is bad (shorted).
If infinity is measured, the J-513/U is bad.
d. Test procedure 84.
When sidetone is heard, measure continuity of
the receive signal path from the output of the RT X-MODE plug to input of
the KY-57. (Figure 104)
Remove the CX-13064/U cable from the RT X-MODE plug.
Remove the CX-13061/ cable from the KY-57 RAD jack.
With a jumper wire at P2 of the CX-13061/U, jumper pin G to pin
N. This will keep J-3513/U relay energized, as when the KY-57 is
connected.
Measure continuity from the CX-13064/U P3 pin A to the CX-13061/U
P2 pin A.
If zero ohms is measured, the KY-57 is bad.
If infinity is measured, remove the jumper from the CX-13061/U.
Remove the RT from the MT-1029.
Remove the CX-13061/U cable from the J-3513 J3.
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