TM
55-4920-244-14
y. Secure tester after operation in ac-
by using the insulation resistance check de-
cordance with paragraph 2-14.
scribed in paragraph 2-10.
b. Engine Thermocouples Out of Calibra-
tion. When the engine thermocouples are sub-
Inoperative or Out of Calibration in
jected to strong reducing or oxidizing atmos-
Engine Paralleling Harness.
pheres for a period of time, they will drift ap-
a. Engine Thermocouples Inoperative.
preciably from their original calibration. On
engine parrallel harnesses when individual engine
This error is found in the regular testing of
thermocouples can be removed, the engine ther-
engine thermocouples with the continuity check
probe (para. 2-12) and will be either a broken
mocouples may be bench checked individually
using one heater probe connected to the tester in
lead wire in the engine paralleling harness or a
accordance with paragraph 2-17. On engines
short to ground. If the trouble is a short to
where individual thermocouples can not be re-
ground, the thermocouple current can leak off
moved, the entire thermocouple harness should
and never show on the aircraft EGT indicator.
be removed for bench check.
However, this grounded condition can be found
2-12
