TM 55-4920-401-13&P
Table 1-13. Accessory Functions.
Index Number
(Figure 4-
Accessory
Function
—
—
1
Switch Box
During trim, permits thermocouple signal to be mon-
itored on cockpit indicator or on tester. Used only with
D’Arsonval indicators.
2
Junction Box
Connects to heater cable and probes. Power distribution
box for probes. Also combines signals from probe thermo-
couples to obtain average thermocouple signal.
3
Heater Cable
Connects to junction box. Supplies power from tester to
heat probes. Also carries probe thermocouple signal to
tester.
4
Check Cable
Connects engine thermocouple signal to tester.
5
Instrument Cable
Connects tester to a variety of adapters including re-
sistance check adapter, insulation check adapter, indi-
cator check adapter, RPM adapter, and RPM indicator
adapter.
6
Extension Handle
Where thermocouples are relatively inaccessible, exten-
sion handle holds probes and allows them to be properly
positioned.
7
Power Cable
Supplies power to tester.
8
RPM Check Adapter
During trim, supplies tach generator output to tester
through instrument cable and to cockpit RPM indicator,
simultaneously. Connects at tach indicator.
9
Insulation Check Adapter Connects through instrument cable to tester. Checks in-
sulation resistance of complete aircraft thermocouple
system.
10
EGT Indicator Check
Connects through instrument cable to tester. Provides
Adapter
calibrated signal to check cockpit indicator.
11
Resistance Check
Connects through instrument cable to tester. Checks re-
Adapter
sistance of complete aircraft thermocouple system.
12
Heater Probes
Heat aircraft thermocouples. Probes include their own
thermocouples which permit their temperatures to be in-
dicated on the tester. Probes must be matched to engine
thermocouples. Connect to junction box.
13, 14
Check Cable Adapter
Adapts check cable to engine harness junction connector.
1-44
