Figure 2-73. Removal of ECU panel assembly.

TM 5-6675-250-34

Table 2-1. Troubleshooting - Continued

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

CAUTION

To avoid damage to the electrical connectors, alternately back-off each of the two attaching screws when removing the

connectors.

c. Disconnect two electrical connectors (2A1P5 and 2A1P6) by unfastening two screws at each connector.

Remove printed circuit board.

d. Inspect printed circuit board for visual evidence of cracked circuits, corrosion, burns or other

evidence of defects.

Replace a bad printed circuit board.

CAUTION

To avoid damaging the electrical connectors, alternate tightening each of the two screws during reassembly.

(1). Install a good printed circuit board, but do not tighten mounting screws. Connect the two

electrical connectors and secure by tightening two screws. Fasten ten screws that secure printed

circuit board to mounting brackets.

(2). Install electronic control panel assembly in case and secure with eight captive screws.

Step 2. Check for defective TEST SELECT switch (2A1S1) or MODE SELECT switch (2A1S3).

a. Loosen the eight captive screws and lift the electronics control panel assembly from the case (figure 2-73).

CAUTION

Figure 2-73. Removal of ECU panel assembly.

b. Unfasten ten screws securing the printed circuit board to mounting brackets and loosen the board to

obtain access to electrical connectors.

CAUTION

To avoid damage to the electrical connectors, alternately back-off each of the two attaching screws when removing the

connectors.

c. Disconnect two electrical connectors (2A2J5 and 2A2J6) by unfastening two screws at each connector.

d. Use an ohmmeter and check continuity of TEST SELECT switch (2A2S1) between input pins (A, B, and C)

and output pins (1 thru 8).

Replace a bad switch.

(1). Place MODE SELECT switch to GC position (fig. 2-74).

(2). Place TEST SELECT switch to source voltage position.

2-60