TM 1-1520-238-T-5
Change 4
8–109
8–41.
CPG ENGINE INSTRUMENT VERTICAL DISPLAYS AND DIGITAL READOUTS
8–41
BRIGHTNESS – DOES NOT CHANGE WHEN MANUAL DIM CONTROL IS ROTATED
(WITH CPG DIM/TEST PANEL INSTALLED)
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. Check CPG dim/test panel for resistance
between (A517)J1–7 and (A517)J1–8.
Is resistance between 2250 and 2750 ohms?
YES
Go to step 2.
NO
Replace CPG dim/test panel
(TM 1-1520-238-23).
2. Check manual DIM control potentiometer on
CPG dim/test panel for resistance between
(A517)J1–12 and (A517)J1–8.
Does reading increase from between 0 and
250 ohms to between 2250 and 2750 ohms
when control knob is rotated clockwise?
YES
Go to step 3.
NO
Replace CPG dim/test panel
(TM 1-1520-238-23).
3. Check for open between:
P1092–7 and P1093–8,
P1092–12 and P1093–9,
P1092–8 and P1093–10.
Does open exist?
YES
Repair open wire.
Go to paragraph 8–10.
NO
Go to step 4.
4. Check for short between:
P1092–7 and ground,
P1092–8 and ground,
P1092–12 and ground.
Does short exist?
YES
Repair shorted wire.
Go to paragraph 8–10.
NO
Replace CPG ENG INST
dimmer power supply
(TM 1-1520-238-23).
END OF TASK
