Sharp R-4A56, Руководство по обслуживанию

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R-4A56
14
TEST PROCEDURES (CONT'D)
PROCEDURE
LETTER
COMPONENT TEST
If the display fails to clear when the STOP/CLEAR pad is depressed, first verify the ribbon is making good
contact, verify that the door sensing switch(stop switch) operates properly; that is the contacts are closed
when the door is closed and open when the door is open. If the door sensing switch(stop switch) is good,
disconnect the flat ribbon that connects the key unit to the control unit and make sure the door sensing
switch is closed (either close the door or short the stop switch connecter). Use the Key unit matrix
indicated on the control panel schematic and place a jumper wire between the pins that correspond to
the STOP/CLEAR pad making momentary contact. If the control unit responds by clearing with a beep
the key unit is faulty and must be replaced. If the control unit does not respond, it is a faulty and must
be replaced. If a specific pad does not respond, the above method may be used (after clearing the control
unit) to determine if the control unit or key pad is at fault.
L KEY UNIT TEST
KEY UNIT
STOP
CLEAR
P O W E R
L E V E L
G-12
G-11
G-10
G-9
G-8
G-7
G-6 G-5
G-4 G-3
G-2
G-1
L E S S
M O R E
1
2 3 4
5
6 7
8 9 0
A U T O
C O O K
A U T O
S T A R T
C L O C K
EASY
DEFROST
Reheat
Beverage
/Soup
I N S T A N T
C O O K
S T A R T
R i c e
&
P a s t a
F r o z e n
D i n n e r
4 X
3 X 2 X
B a c o n
Casseroles C h i c k e n
P i e c e s
R e h e a t
P i e /
P a s t r i e s
F i s h
F i l l e t s
M RELAY TEST
1. CARRY OUT 3D CHECKS.
2. Disconnect the leads from the primary of the power transformer, Make sure that the leads remain
isolated from other oven components and chassis. (Use insulation tape if necessary)
3. Close the door.
4. Reconnect the supply.
5. Check the voltage between Pin Numbers 3 and 5 of 3-pin connector (A) on the control unit with an
A.C. voltmeter. The meter should indicated 240 volts, if no cheak oven circuit.
6. RY1 AND RY2 Test
These are operated by D.C. voltage. Check voltage at the relay coil with a D.C. voltmeter during the
microwave cooking.
DC. voltage indicated ................... Defective relay.
DC. voltage not indicated ................ Check diode which is connected to the relay coil. If diode is
good, control unit is defective.
RELAY SYMBOL OPERATIONAL VOLTAGE CONNECTED COMPONENTS
RY1 APPROX. 26.5V D.C. Oven lamp / Turntable motor / Cooling fan motor
RY2 APPROX. 25.8V D.C. Power transformer