Touch Control Panel Assembly - Sharp R-6R50 Service Manual

PROCEDURE
TEST PROCEDURES (CONT'D)
COMPONENT TEST
NOISE FILTER UNIT TEST
Disconnect the oven from the power supply. Connect ohmmeter leads to connector N and L on
the noise filter unite, connector N and white terminal, or connector L and red terminal. And then
measure the each resistance. ;
N og
WINE CAOSS CAPACITOR ,
O,22u/AC2G0V
! Gaoksonw
LINE BYPASS CAPACITOR LINE BYPASS CAPACITOR
0.0047 fAC250V B07 WACO
10M/0,5W
LINE CROSS CAPACITOR
0,1p/AC250V
1.665/0,5M
LINE BYPASS CAPACITOR
0.0033 ,)/AC250¥
LINE BYPASS CAPACITOR
G.0033 pfaczsoy
VOM/IDL BW
Or rr Oe ere Gn a a er Ge SS pe cD ay
R-6R50 R-6G50/6G52/6R70
MEASURING POINTS INDICATION OF OHMMETER
Between connector N and L - R-6R50: Approximately 1.5M Q
R-6G50/6G52/6R70: Approximately 680k Q
lf the ohmmeter does not indicate above resistance, replace the noise filter unit. In case the
ohmmeter indicates open circuit when testing between connector L and terminal RED, check the
fuse on the noise filter unit. If the fuse blows, replace it.
TOUCH CONTROL PANEL ASSEMBLY TEST
The touch contro] panel consists of circuits including semiconductors such as LSI, ICs, etc.
Therefore, unlike conventional microwave ovens, proper maintenance cannot be performed with
only a voltmeter and ohmmeter. In this service manual, the touch control panel assembly is di-
vided into two units, Control Unit and Key Unit, trouble shooting by unit replacement is de-
scribed according to the symptoms indicated.
1. Key Unit.
The following symptoms indicate a defective key unit. Replace the key. unit.
a) When touching the pads, a certain pad produces no signal at all.
_ b) When touching a number pad, two figures or more are displayed. _
c) When touching the pads, sometimes a pad produces no signal.
2. Control Unit 2:
The following symptoms indicate a defective control unit. Replace the contro! unit.
2-1 In connection with pads.
a) When touching the pads, a certain group of pads do not produce a signal.
b) When touching the pads, no pads produce a signal.
2-2 In connection with indicators ;
a) Ata certain digit, all or some segments do not light up.
b) Ata certain digit, brightness is low.
c) Only one indicator does not light up. ©
d) The corresponding segments of all digits do not light up; or they continue to light up.
e) Wrong figure appears. .
f) Accertain group of indicators do not light up.
g) The figure of all digits ficker.
2-3 Other possible troubles caused by defective control unit.
a) Buzzer does not sound or continues to sound.
_b) Clock does not operate properly.
¢) Cooking is not possible.
d) Proper temperature measurement is not obtained.
(RD82802U)
16
PROCEDURE
| 4. | Pattern at "a" and "b" are broken.
R-6R50(W)/(B
R-6R70(W)/(B
TEST PROCEDURES (CONT'D)
COMPONENT TEST
RELAY TEST
Remove the outer case and check voltage between Pin Nos. 5(7) and 7(9) of the 7(9)-pin
connector A on the contro! unit with an A.C. voltmeter.
The meter should tndicate 220 volts, if not check oven circuit.
Shut-off,Cook and Heater Relay Test
These relays are operated by D.C. voltage.
Check voltage at the relay coil with a D.C. voltmeter during the microwave cooking or grill
cooking operation.
DC. voltage indicated a... Defective relay. B e a :
DC. voltage not indicated ........ Check diode which is connected to the relay coll. If diode is
good, contro! unit is defective.
RELAY SYMBOL OPERATIONAL CONNECTED COMPONENTS
VOLTAGE
avi
aYS (HEATER)
oz
RYS
PROCEDURES TO BE TAKEN WHEN THE FOIL PATTERN ON THE PRINTED WIRING
BOARD(PWB) IS OPEN.
To protect the electronic circuits, this model is provided with a fine foil pattern added to the
primary on the PWB, this foil pattern serves as a substitute coil. If the foil pattern is open, follow
the troubleshooting guide given below for repair.
Problem: POWER ON, indicator does not light up.
TEPS| OCCURANCE CAUSE OR CORRECTION
1 The rated voltage is not applied to POWER terminal | Check supply voltage and oven power cord,
|of CPU connector (CN-A) ;
2 The rated voltage is applied to primary side of pawer | Power transformer or secondary circuit defective.
transformer. : ~ | Check and repair. vax?
Only pattern at "a" is broken. *Insert jumper wire 1 and soijder.
.|*tnsert the coil RCJLF2003YAZZ between. "c" and|... ..—
NOTE:* At the time of these repairs, make visual in-
spection of the varistor for burning damage
and examine the transformer with tester for the
presence of layer short-circuit (check primary
coil resistance).
Hf any abnormal condition is detected, replace
the defective parts.
({RDB2X04L))
17