Power Transformer Test - Sharp R-3A53 Service Manual

R-3A53
R-3A53B
TEST PROCEDURES (CONT'D)
PROCEDURE
LETTER
COMPONENT TEST
B
POWER TRANSFORMER TEST
WARNING: High voltages and large currents are present at the secondary wind-
r---- _
ing and filament winding of the power transformer. It is very dangerous to work
near this part when the oven is on.
NEVER make any voltage measurements of the
high-voltage circuits, including the magnetron filament.
CARRY OUT 3D CHECKS.
Disconnect the leads to the primary winding of the power transformer. Disconnect the filament
and secondary winding connections from the rest of the HV circuitry. Using an ohmmeter, set
on a low range, it is possible to check the continuity of all three windings. The following
readings should be obtained :-
a. Primary winding ----------I .96 ohms approximately.
b. Secondary winding - - - - - - -97.2 ohms approximately.
c. Filament winding ---------less than 1 ohm.
If the reading obtained are not as stated above, then the power transformer is probably faulty
and should be replaced.
CARRY OUT 4R CHECKS
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