Table 2-1. Direct Support Troubleshooting Guide (Continued)
TEST OR INSPECTION
1. Heater power supply does not work on AC power. (Ref. Schematic diagram FO-1, sheet 11, schematic line 1129).
Shut down ROWPU and generator. Refer to electrical drawings in Appendix D. Check continuity, point-to-point, from
transformer T2(1C) (REF: Interconnection diagram FO-2, Sheet 10) to J17F (REF: Interconnection diagram FO-2,
Sheet 9). Repeat the procedure from T2(2C) to J17G.
(a) Repair any loose or damaged wires (para. 2-20).
(b) Replace/repair connector J17, if faulty (para. 2-21).
(c) Replace relay K27 (REF: Interconnection diagram FO-2, Sheet 8) if the A4 contacts are open (para.
(d) Replace the heater switch, SS8 (REF: Interconnection diagram FO-2, Sheet 13), if faulty (para. 2-24).
Circuit breaker 11 (REF: Interconnection diagram FO-2, Sheet 8) is a ground fault
breaker. High humidity or moisture around device controlled by this breaker may
occasionally cause trouble, Check that atmospheric moisture is not causing the tripping
by drying out anything controlled by this breaker, including wire connections.
(e) Replace circuit breaker CB11 if it is faulty (para. 2-23).
2. Power supply has input power but low or no output power. (Ref. Schematic diagram FO-1, sheet 11, schematic lines
1129 and 1131-1132).
Wire must be disconnected to check for continuity.
Shut down ROWPU and generator. Refer to the electrical schematic Appendix D. Disconnect connector P2
(REF: Interconnection diagram FO-2, Sheet 14) at the power supply. Open the power supply electrical access
panel. Check the MOVs (REF: Interconnection diagram FO-2, Sheet 16) for physical damage or signs of
shorting. Remove the MOVs and check for continuity across their terminals.
(a) Repair any loose or damaged wires (para. 2-53).
(b) Replace any MOV which is physically damaged or shows continuity between terminals (para. 2-53).
Disconnect the power supply output cable assemblies. Check each cable, point-to-point for continuity on
Replace/repair any cable that is faulty (para. 2-53 and 2-18).
Electrical high voltage can cause serious injury or death. Some tests performed in
troubleshooting require power to be connected. Always take proper measures to ensure
Connect the power supply output cable assemblies and connector P2. Power up the ROWPU. Turn on the
heater power supply switch. Check for 24-28 VDC across the+ power supply terminals.
Replace the power supply if output voltage is less than 24 VDC (para. 2-53).