Sharp R-211A, Service Manual

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12
R-211A
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
ON: Meter indicates closed. OFF: Meter indicates open.
Check results: If any of the condition as described in the table are not obtained, then the timer should
be replaced.
CARRY OUT 4R CHECKS.
DEFROST SWITCH - CONTACTS
Before proceeding with this part of the test, check the relay coil as outlined above.
WARNING: This test requires the oven to be operated with supply connected.
Follow the instruction below carefully.
1. CARRY OUT 3D CHECKS.
2. Disconnect the leads to the primary of the power transformer. Make sure that the leads remain
isolated from other oven components and chassis.
3. Disconnect the leads from terminals 1 and 3 of the timer, make sure that these leads remain
isolated from other components and the oven chassis (use insulation tape if necessary). Do not
disconnect leads from terminals 1 and 2.
4. Securely clip the leads of an ohmmeter across terminals 1 and 3 of the timer. (Make sure the meter
can be read easily without being touched during the test.)
5. Close the door of the oven.
6. Connect the supply.
7. Set the TIMER to several minutes.
8. Without touching the meter or any part of the oven make a note of the time which the ohmmeter
indicates S.C. and O.C. in each power level as described in the table.
9. Set the MICROWAVE TIMER to 0 (zero).
10.CARRY OUT 3D CHECKS.
11.Disconnect meter from terminals 1 and 3 of the timer.
12.Disconnect meter leads and reconnect the leads to the primary of the power transformer.
VARI-MODE ON TIME OFF TIME
HIGH (approx. 100% power) 30 sec 0 sec.
MEDIUM DEFROST (approx. 45% power) 13.5 sec 16.5 sec.
S.C. = Short circuit O.C. = Open circuit
Timer motor with defrost switch
M
1
4 2
3
SW1
(Main Switch)
SW2
(Defrost Switch)