TM 11-5820-765-34
Defect
test:
Set multimeter to RX1000.
Connect
leads
across
meter
terminals;
take
reading.
Multimeter should read 50,000 ohm
resistance
across
terminals.
Different reading indicates defect.
Accuracy test:
Set multimeter to RX1.
Parallel-connect Voltmeter AN/USM-98A across meter's terminals.
Check zero-adjust - move zero-adjust screw in both directions.
Needle on Ml scale should be moveable above and below zero line.
Meter M2
Function: 50-millivolt meter
Test
equipment:
Voltmeter
AN/USM-98A
Accuracy test:
Parallel-connect voltmeter across meter terminals.
Check zero-adjust movement.
Needle on M2 scale should be moveable above and below zero line.
Controlled Rectifiers
Test equipment: Multimeter TS-352B/U
Measure: Internal resistance
Set multimeter to RX1.
Procedure:
Remove
panel(s).
Disconnect gate and cathode leads of rectifier being tested.
Tests:
Anode-cathode
resistance:
Connect
multimeter
leads
to
opposite
sides
of
rectifier.
Rectifier defective if reading shows: O ohms in both directions.
1 megohm or higher in both directions.
Gate-cathode resistance:
Reverse leads.
Rectifier defective if reading shows 5000 ohms or higher (Indicates open circuit).
NOTE
Reading for gate-cathode resistance should be approximately 1000 ohms
(low resistance scale on ohmmeter).
Reconnect rectifier leads.
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