TM 55-4920-401-13&P
Table 1-12. Indicator and Control Functions.
Indicator or Control
Function
.
A/C IND ADJ (INCREASE)
Adjusts test signal for aircraft temperature
potentiometer
indicator.
AMB TEMP potentiometer
Controls equivalent ambient temperature electrical
signal for standard day correction circuit.
CAL ADJ potentiometer
Calibrates related indicator to internal calibration
signal.
DISPLAY (BRIGHT)
Adjusts brightness of indicator displays.
FUNCTION SELECT switch
A seven-position switch that selects the circuit of
the function being performed by the tester.
INSULATION CHECK meter
Indicates insulation resistance of engine tem-
perature circuit during insulation resistance check.
INSULATION CHECK switch
Selects range of INSULATION CHECK meter.
MASTER POWER switch
Applies and removes power from tester,
POWER TO TEST switch
Tests all indicator displays.
PROBE CONTROL potentiometer
Adjusts the test temperature of the temperature
probe.
PROBE POWER lamp
Glows while probes are heating, turns off during
probe control overshoot, then blinks rapidly when
test temperature is reached.
RESISTANCE & A/C INDICATOR CHECK switch
Places proper resistance in bridge circuit when
checking resistance of engine thermocouple
harness or checking aircraft indicator.
RESISTANCE CHECK meter
Indicates resistance error of aircraft temperature
circuit.
% RPM indicator
Indicates N1 and N2 % rpm.
RPM switch
Selects N1 or N2 rpm. Calibration of % RPM indi-
cator is displayed when switch is in CAL 100% RPM
position.
SPREAD switch
With FUNCTION SELECT switch in SPREAD posi-
tion, individual thermocouple signals applied to
SPREAD CABLE receptacle can be read on TEMP°
C indicator. In ALL position
couple signals is displayed.
average of all thermo-
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