Sharp R-211A, Руководство по обслуживанию

Страница: 12 / 28

10
R-211A
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
E SWITCH TEST
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 10M
Ω
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 M
Ω
because of its internal 10M
Ω
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.
Isolate the switch to be tested and using an ohmmeter check between the terminals as described in
the following table.
CARRY OUT 3D CHECKS.
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, 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.
The resistance of monitor resistor is approx. 0.8 ohms.
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 thermal cut-out. Then using an ohmmeter, make a
continuity test across the two terminals as described in the below.
CARRY OUT 4R CHECKS.
Table: Temperature Fuse or Thermal Cut-out Test
Temperature of Temperature of Indication of
"ON" condition "OFF" condition ohmmeter
Parts Name (closed circuit). (open circuit). (When room
(˚C) (˚C) temperature is
approx. 20˚C.)
Temp. fuse 120˚C This is not resetable Above 120˚C Closed circuit
type.
Thermal cut-out
Below 75˚C Above 95˚C Closed circuit.
COM; Common terminal,
NO; Normally open terminal
NC; Normally close terminal