Sharp R-24ST Service Manual

R-24ST/R-2B34 - 14
CARRY OUT
3D CHECKS
Isolate the switch to be tested and using an ohmmeter check between the terminals as described in the
following table.
TEST PROCEDURES
E SWITCH TEST
COM; Common terminal
NO; Normally open terminal
NC; Normally close terminal
Table: Terminal Connection of Switch
Plunger Operation COM to NO COM to NC
Released Open circuit Short circuit
Depressed Short circuit Open Circuit
If incorrect readings are obtained, or replace the switch.
CARRY OUT
4R CHECKS.
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 10 MΩ
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 10 MΩ
resistance.
F. When the internal wire is opened in the high voltage capacitor, the 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
C HIGH VOLTAGE RECTIFIER TEST
CARRY OUT 3D CHECKS.
Isolate the high voltage rectifier assembly from the HV circuit. The high voltage rectifier can be tested
using an ohmmeter set to its highest range. Connect the ohmmeter across the terminal of the high
voltage rectifier and note the reading obtained. Reverse the meter leads and note this second reading.
The normal resistance is infinite in one direction and more than 100 kΩ in the other direction.
CARRY OUT
4R CHECKS.
NOTE: FOR MEASUREMENT OF THE RESISTANCE OF THE RECTIFIER, THE
BATTERIES OF THE MEASURING INSTRUMENT MUST HAVE A VOLTAGE AT LEAST 6
VOLTS, BECAUSE OTHERWISE AN INFINITE RESISTANCE MIGHT BE SHOWN IN BOTH
DIRECTIONS.
D HIGH VOLTAGE CAPACITOR TEST
PROCEDURE
LETTER COMPONENT TEST

Sharp R-24ST Specifications

General

Brand	Sharp
Model	R-24ST
Category	Microwave Oven
Language	English