TM 1-1520-238-T-4
6–137
6–64.
HOD XMN 1 READING – DISPLAYS 140 C OR HIGHER OIL TEMPERATURE
6–64
Tools:
Nomenclature
Part Number
Tool Kit, Electrical
SC518099CLA06
Repairer’s
Tool Kit, Powertrain
SC518099CLA013
Repairer’s
Multimeter, Digital
AN/PSM-45
Personnel Required:
68D
Aircraft Powertrain Repairer/NDI
68F
Aircraft Electrician
References:
TM 1-1520-238-23
TM 9-1230-476-20-2
Equipment Conditions:
Ref
Condition
TM 1-1520-238-23
Access provisions –
L325, T250L, T250R,
T290L, T290R and
T325 access doors
open
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.
NOTE
If HOD is indicating 140 C or higher for
main transmission oil temperature, either
OIL HOT MAIN XMSN 1 or 2 indicator
may be lighted or both, depending upon
temperature difference readings at
temperature transducers. Transmission
temperature transducer 2 may be
considerably cooler than 1 due to hot oil
being pumped into transmission 1 sump
first. Therefore, if OIL HOT MAIN XMSN 1
indicator is on and 2 off, the 2 circuitry
may not necessarily require
troubleshooting.
1. Check caution/warning panels OIL HOT MAIN
XMSN 1 and 2 indicators.
Is either OIL HOT MAIN XMSN 1 or 2 indicator
light lighted?
YES
Go to step 3.
NO
Go to step 2.
2. Check for 28 VDC between P755–2 and
P755–6.
Is voltage present?
YES
Go to step 4.
NO
Go to step 5.
3. Check transmission oil heat exchangers
(TM 1-1520-238-23).
Are heat exchangers operating properly?
YES
Replace main transmission
(TM 1-1520-238-23).
NO
Replace transmission heat
exchanger (TM 1-1520-238-23).
4. Check for 10 VDC between P682–87 and
P682–86.
Is voltage present?
YES
Refer to TM 9-1230-476-20-2 to
troubleshoot multiplex
subsystem.
NO
Go to step 6.
5. Check for 28 VDC between P755–2 and ground.
Is voltage present?
YES
Repair wire between:
P755–6 and GS572–H.
Go to paragraph 6–13.
NO
Refer to chapter 4 to
troubleshoot power plants.
