Troubleshooting and Repair (Temperature Circuit)

TM 55-4920-411-13&P

(11) If wiring checks good, refer to Troubleshooting

(6) If S3 checks good, check wiring between S3 and

J2.

Hold switch S3 in HI OIL TEMP position.

Check connector J2 for continuity between pins J and

H and J and G when switch S3 is held in HI OIL TEMP

RESULT: Lamp L5 shall light.

position.

(12) If L5 does not light, open simulator and check

RESULT: Continuity absent from J to H and pre-

switch S3 for continuity. Replace S3, if defective.

sent from J to G.

(13) If S3 checks good check wiring between S3, the

(7) If result is not true, open simulator and check

display board and connector J2.

switch S3 for continuity.

(14) 1 f wiring checks good, refer to Troubleshooting

(8) If S3 checks good, check wiring between S3 and

J2. Connect a dc power supply, set at 28 vdc, between

pins J(+) and P(-) of connector J2. Figure 4-5 shows Pin

(15) Compensator Resistor R34 on the Signal Gen-

arrangement of J2.

erator Board should measure approximately 10.3 0.2

ohms at 20 C (68 F) and R35 should measure approx-

Hold switch S3 in LOP position.

imately 22.4 0.2 ohms at 20 C (68 F).

RESULT: Lamp L6 shall light.

(16) Different ambient temperature will effect com-

(9) If L6 does not light, open simulator and check

pensator resistors resistance readings. If R34 and R35

switch S3 for continuity. Replace S3, if defective.

have to be replaced, send unit to Depot for repair. When

resistors R32, R33 and diodes CR12 are replaced, per-

(10) If S3 checks good, check wiring between S3, the

form temp check, para 4-10a.

display board and connector J2.