TM 1-1520-238-T-5
Change 7
8–87
8–21.
PILOT NG RPM% INDICATOR – DOES NOT INDICATE FULL SCALE OR SHOW DIGITAL
8–21
888 OR VERTICAL SCALE INDICATORS HAVE EVERY OTHER LAMP NOT LIGHTED
Tools:
Nomenclature
Part Number
Tool Kit, Electrical
SC518099CLA06
Repairer’s
Multimeter, Digital
AN/PSM-45
Personnel Required:
68X
Armament/Electrical Systems Repairer (2)
References:
TM 1-1520-238-23
WARNING
Turn off power before detaching or
attaching wires and connectors. High
current 28 VDC or 115 VAC is present.
Failure to do so could result in death or
serious injury.
1. On pilot dim/test panel, hold
DGT OFF/NORM/TST switch to TST. Check for
short between P67–17 and ground.
Does short exist?
YES
Go to step 2.
NO
Repair open wire between:
P67–17 and (A326)TB1–50–D.
2. Check for 2 to 5 VDC at P67–7 and P67–8.
Is voltage present?
YES
Go to step 3.
NO
Go to step 6.
3. Check for:
5 VDC at P67–12,
–8 VDC at P67–13,
8 VDC at P67–14.
Are voltages present?
YES
Go to step 4.
NO
Go to step 5.
4. Check for open between:
P67–9 and GS427–C,
P67–10 and GS427–D,
P67–11 and GS427–E.
Does open exist?
YES
Repair open wire.
Go to paragraph 8–10.
NO
Replace pilot NG RPM%
indicator (TM 1-1520-238-23).
5. Check for open between:
P67–12 and P401–18,
P67–13 and P401–12,
P67–14 and P401–4.
Does open exist?
YES
Repair open wire.
Go to paragraph 8–10.
NO
Replace SDC
(TM 1-1520-238-23).
6. Check for open between:
P67–7 and P401–25,
P67–8 and P401–31.
Does open exist?
YES
Repair open wire.
Go to paragraph 8–10.
NO
Replace SDC
(TM 1-1520-238-23).
END OF TASK
