Sharp Carousel R-3S56 Service Manual - Page 12

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R-3S56
PROCEDURE
LETTER
CARRY OUT 4R CHECKS.
NOTE: FOR MEASUREMENT OF THE RESISTANCE OF THE RECTIFIER, THE BATTERIES OF THE
D
HIGH VOLTAGE CAPACITOR TEST
CARRY OUT 3D CHECKS.
A. Isolate the high voltage capacitor from the circuit.
B. Continuity check must be carried out with measuring instrument which is set to the highest resistance
range.
C. A normal capacitor shows continuity for a short time (kick) and then a resistance of about 10MΩ after it has
been charged.
D. A short-circuited capacitor shows continuity all the time.
E. An open capacitor constantly shows a resistance about 10 MΩ because of its internal 10MΩ resistance.
F. When the internal wire is opened in the high voltage capacitor shows an infinite resistance.
G. The resistance across all the terminals and the chassis must be infinite when the capacitor is normal.
If incorrect reading are obtained, the high voltage capacitor must be replaced.
CARRY OUT 4R CHECKS.
E
SWITCH TEST
CARRY OUT 3D CHECKS.
Isolate the switch to be tested and using an ohmmeter check between the terminals as described in the
following table.
If incorrect readings are obtained, make the necessary switch adjustment or replace the switch.
CARRY OUT 4R CHECKS.
F
MONITOR RESISTOR TEST
CARRY OUT 3D CHECKS.
Disconnect the leads from the monitor resist. Using an ohmmeter and set on a low range. Check between
the terminals of the monitor resistor.
If incorrect readings are obtained, replace the monitor resistor.
CARRY OUT 4R CHECKS.
G
TEMPERATURE FUSE OR THERMAL CUT-OUT TEST
CARRY OUT 3D CHECKS.
Disconnect the leads from the terminals of the temperature fuse or thermal cut-out. Then using an
ohmmeter, make a continuit test across the two terminals as described in the below.
CARRY OUT 4R CHECKS.
Parts Name
Temperature fuse 150˚C
Thermal cut-out 95˚C
TEST PROCEDURES (CONT'D)
MEASURING INSTRUMENT MUST HAVE A VOLTAGE AT LEAST 6 VOLTS, BECAUSE
OTHERWISE AN INFINITE RESISTANCE MIGHT BE SHOWN IN BOTH DIRECTIONS.
Table: Terminal Connection of Switch
Plunger Operation
Released
Depressed
The resistance of monitor resistor is approx. 0.8 ohms.
Temperature of "ON" condition
(closed circuit) (˚C)
This is not resetable type.
Below 75˚C
COMPONENT TEST
COM to NO
COM to NC
O.C.
S.C.
S.C.
O.C.
Table: Thermal cut-out Test
Temperature of "OFF" condition
(open circuit) (˚C)
Above 150˚C
Above 95˚C
10
COM; Common terminal,
NO;
Normally open terminal
NC;
Normally close terminal
S.C.; Short circuit
O.C.; Open circuit
Indication ofohmmeter
(When room temperature
is approx. 20˚C)
Closed circuit.
Closed circuit.