TM 1-1520-238-T-5
Change 7
8–83
8–17.
ALL PILOT ENGINE INSTRUMENTS – DO NOT INDICATE FULL SCALE OR SHOW DIGITAL
8–17
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-T-6
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. Check for 28 VDC at:
P400–57 and P400–58,
P401–57 and P401–58.
Is voltage present?
YES
Go to step 2.
NO
Go to step 3.
2. On pilot dim/test panel, set and hold
DGT OFF/NORM/TST switch to TST. Check for
short between wire end of (A326)TB1–50–S and
ground.
Does short exist?
YES
Replace SDC
(TM 1-1520-238-23).
NO
Go to step 4.
3. Check for 28 VDC at:
(A76):
J1–L and J1–M.
(A77):
J1–8 and J1–10.
Is voltage present?
YES
Repair open wire between:
P463–L and P400–57,
P463–M and P400–58,
P766–8 and P401–57,
P766–10 and P401–58.
Go to paragraph 8–10.
NO
Refer to TM 1-1520-238-T-6 to
troubleshoot circuit protection
system (dc emergency bus –
pilot station).
4. Check for open between:
P787–4 and GS425–H,
P787–3 and P409–A2.
(A326):
J4–A2 and TB1–50–S.
Does open exist?
YES
Repair open wire.
Go to paragraph 8–10.
NO
Replace pilot dim/test panel
(TM 1-1520-238-23).
END OF TASK
