Table 4-1. General Support Troubleshooting-continued

TM 11-6760-238-34

Table 4-1. General Support Troubleshooting - Continued

SYMPTOM

PROBABLE TROUBLE

CORRECTIVE ACTION

7. WITH EXCEPTION OF THE AC POWER, DC POWER, AND FWD, CENTER AND AFT LAMPS (DS3, DS4, DS5),

PANEL LAMPS DO NOT LIGHT (step 8)

Defective MASTER switch S3

Replace MASTER switch (para 4-6 h and i)

8. SENSOR CAL LAMP DS2 DOES NOT LIGHT(step 9), AC POWER AND DC POWER LAMPS ON

a. Defective LOCAL PLANE SHUTTER switch S8

Replace FOCAL PLANE SHUTTER switch (para 4-6 h and i)

b. Defective phototransistor assembly A1OA3

Replace phototransistor assembly (para 4-7a and h)

9. SENSOR CAL LAMP DS2 DOES NOT LIGHT (step 10), AC POWER AND DC POWER LAMPS ON

a. Defective FOCAL PLANE SHUTTER switch S8

Replace FOCAL PLANE SHUTTER switch (para 4-6h and l)

b. Defective phototransistor assembly A10A2

Replace phototransistor assembly (para 4-7a and b)

10. SENSOR CAL LAMP DS2 DOES NOT LIGHT (step 11), AC POWER AND DC POWER LAMPS ON

a. Defective FOCAL PLANE SHUTTER switch S8

Replace FOCAL PLANE SHUTTER switch (para 4-6 h and l)

b. Defective phototransistor assembly A10A1

Replace phototransistor assembly (para 4-7 a and b)

11. OPER LAMP A9DS4 DOES NOT LIGHT (step 19), DC POWER LAMPS ON

Defective MASTER switch S3

Replace MASTER switch (para 4-6 h and i)

12. RECY LAMP A9DS3 DOES NOT LIGHT (step 21), DC POWER LAMPS ON

Defective MASTER switch S3

Replace MASTER switch (para 4-6 h and i)

13. DATA LAMP A9DS1 DOES NOT LIGHT (step 23), DC POWER LAMPS ON

Defective MASTER switch S3

Replace MASTER switch (para 4- 6 h and i)

14. ELECT FLASH LAMP A9DS2 DOES NOT LIGHT (step 25), DC POWER LAMPS ON

Defective MASTER switch S3

Replace MASTER switch (para 4-6 h and i)

15. 90 LAMPS A5DS3 AND A5DS4 DO NOT LIGHT (step 27), DC POWER LAMPS ON

Defective MASTER switch S3

Replace MASTER switch (para 4-6 h and i)

16. AUTO LAMP A7DS1 DOES NOT LIGHT (step 27), DC POWER LAMPS ON

Defective MASTER switch S3

Replace MASTER switch (para 4-6 h and i)

17. D LAMP A2DS3 DOES NOT LIGHT (step 29), DC POWER LAMPS ON

Defective MASTER switch S3)t

Replace MASTER switch (para 4-6 h and i)

equivalent) is used to measure voltages.

4-4. Signal Substitution

NOTE

Signal substitution procedures quickly enable localization

of a trouble. An oscilloscope, rc bridge, and voltmeter

When connecting the test jumper cables, it may be

may be used in performing signal substitution

necessary to partially remove the fungicide coating to

procedures.

Below are general notes on signal

ensure proper electrical contact. Use acetone (Federal

substitution and signal tracing.

Specification O-A-51) to remove the fungicide from the

a. Test jumper cables are used to apply either +

printed circuit board.

c. After trouble is traced to a circuit, disconnect

28 volt dc power or ground to particular points throughout

the test equipment and perform voltage and resistance

the test panel.

measurements to localize the defective part.

b. A multimeter (Multimeter ANIUSM-223 or

4-2