TM 9-4910-663-34
(1)
Disconnect the main power from the test stand.
(2)
Remove the panel retaining hardware from the sides and front of the control panel (fig 2-5), raise the
control panel, and secure it in the up position with the lock bolt.
(3)
Using an ohmmeter, measure the resistance of resistor R1. The resistance should be 250 ±02.5 ohms.
f.
Removal and Replacement of Starter Coil Resistor R1.
(1)
Disconnect main power from the test stand.
(2)
Remove the panel retaining hardware from the sides and front of the control panel (fig 2-5), raise the
control panel, and secure it in the up position with the lock bolt.
(3)
Unsolder the leads at both ends of resistor R1, remove the 10-32 screws, lockwashers, and nuts, and
remove the resistor.
(4)
Reverse the procedures of steps (1) through (3) to install the replacement resistor.
3-10.
LOAD BANK ASSEMBLY (fig 2-10)
a.
Description. The load bank assembly contains a resistive load bank, a cooling plenum chamber and outlet duct,
and an air-flow actuated mercury switch. The load bank provides resistive loads used during testing of external
components on the test stand. The plenum chamber and outlet duct are part of a forced-air cooling system for the load
bank, and the mercury switch is used to shut down the varidrive if the cooling air flow is restricted. Repair of the load
bank assembly is limited to the removal and replacement of a defective air flow switch and load bank elements. (Repair
of the load bank is covered in paragraph 3-11 below.) Removal and replacement of the air flow switch can be done with
the load bank assembly installed in the test stand.
b.
Removal and Replacement of Air Flow Switch.
(1)
Disconnect main power from the test stand.
(2)
Remove the panel retaining hardware from the upper and lower rear panels of the test stand, and remove
the upper and lower rear panels.
(3)
Disconnect the leads of air flow switch from the terminal block on the load bank assembly.
(4)
Unclip air flow switch from its holder, and remove the switch.
Change 1 3-22
