Table 4-2. Troubleshooting Table - continued.
TEST OR INSPECTION
3. TWO MODULE (MOD) FAILURES ON SAME BACKPLANE - continued.
Do not disconnect RX-TX cable assembly while equipment power is on.
Oscilloscope settings do not change.
Refer to TM 5-6350-280-10 turn equipment off, refer to paragraph 4.6.5 and disconnect RX-TX cable
assembly from backplane not in question, disconnect RX-TX cable assembly from input/output (I/O) CCA
for drawer not in question, and refer to TM 5-6350-280-10 turn equipment on. Position B probe ground
on terminal 6, TX signal return, and B probe on terminal 7 of connector P2, left backplane, or P3 right
backplane. Refer to figure 4-3 and check for TX input signal, lower waveform in figure 4-3.
If TX input signal is present, refer to paragraph 4.6.5 and replace RX-TX cable assembly, otherwise refer
to paragraph 4.6.9 and replace backplane.
4. FOUR MODULE (MOD) FAILURES SAME DRAWER ASSEMBLY.
A volt ohm meter (VOM) is required for this procedure.
Refer to figure 4-4, Appendix E and tables 4-6 through 4-10 for schematics and
Using VOM, check for +5 Vdc, at the +5 Vdc terminal, on any CPU CCA in drawer assembly.
If +5 Vdc is present go to step 10, otherwise go to step 2.
Open rear door of converter multiplexer assembly (CMA) and ensure drawer power cable is plugged into
multiple outlet strip.
If power cable is plugged in go to step 3, otherwise plug power cable into multiple outlet strip.
Using VOM, check for 120 Vac at CMA multiple outlet strip.
If 120 Vac is present go to step 6, otherwise press reset button on CMA multiple outlet strip. If power is
not restored to drawer assembly go to step 4.
Disconnect extension cord from uninterruptible power supply (UPS). Using VOM, check for 120 Vac
output from UPS.
If 120 Vac is available go to step 5, otherwise refer to UPS manual and troubleshoot UPS.
Disconnect CMA multiple outlet strip from extension cord between UPS and CMA. Using VOM check for
120 Vac at end of extension cord.
If 120 Vac is present refer to paragraph 4.6.2 and replace multiple outlet strip, otherwise troubleshoot