Mitsubishi Electric LT-37131 Service Manual page 6

Leakage current check
Before returning the receiver to the customer, leakage current should be measured using following methods.
1. Cold Check
With the alternating current (AC) plug removed from the AC source, place a jumper across the two AC plug prongs.
Connect one lead of an ohm meter to the AC plug and touch the other lead to each exposed metal part (i.e. anten-
nas, handle bracket, metal cabinet, screw heads, metal overlay, control shafts, etc.), particularly any exposed metal
part that has a return path to the chassis. The resistance of the exposed metal parts having a return path to the
chassis should be a minimum of 1Meg Ohm. Any resistance below this value indicates an abnormal condition
and requires corrective action.
2. Hot Check ...Use the circuit shown below to perform the hot check test.
1. Keep switch S1 open and connect the receiver to the measuring circuit. Immediately after
connection, and with the switching devices of the receiver in their operating positions, measure
the leakage current for both positions of switch S2.
2. Close switch S1, energizing the receiver. Immediately after closing switch S1, and with the
switching devices of the receiver in their operating positions, measure the leakage current for both
positions of switch S2. Repeat the current measurements of items 1 and 2 after the receiver has
reached thermal stabilization. The leakage current must not exceed 0.5 milliampere (mA).
MODELS: LT-37131 / LT-37132 / LT-46131 / LT-46231
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