Electrolux EI30SM55JB Technical & Service Manual page 31

Procedure
Letter
TOUCH CONTROL PANEL ASSEMBLY TEST
L
The touch control panel consists of circuits including semiconductors such as LSI, ICs, etc. There-
fore, 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 divided
into two units, Control Unit and Glass Touch Key Unit, and troubleshooting by unit replacement is
described according to the symptoms indicated.
Before testing,
1. Disconnect the power supply cord, and then disassemble as per "Hood Louver Removal",
"Removal Of Oven From Wall" And "Outer Case Removal".
2. Open the door and block it open.
3. Discharge high voltage capacitor. (See Warnings and Instructions on page 3-1)
4. Disconnect the leads to the primary of the power transformer.
5. Ensure that these leads remain isolated from other components and oven chassis by using
insulation tape.
6. After that procedure, re-connect the power supply cord.
Glass Touch Key Unit
1. Check glass touch key unit connection before replacement.
2. Reconnect all leads removed from components during testing.
3. Reconnect the power supply cord after the covers are installed.
4. Run the oven and check all functions.
The following symptoms indicate a defective glass touch 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.
If the keyboard unit is defective.
1. Disconnect the power supply cord and then remove outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor. (See Warnings and Instructions on page 3-1)
4. Replace the door frame assembly.
5. Reconnect all leads removed from components during testing.
6. Reconnect the power supply cord.
7. Run the oven and check all functions.
Control Unit
The following symptoms indicate a defective control unit. Before replacing the control unit, perform
the glass touch key unit test (Procedure M) to determine if control unit is faulty.
1. In connection with indicators:
a) At a certain digit, all or some segments do not light up.
b) At a certain digit, brightness is low.
c) Only one indicator does not light.
d) The corresponding segments of all digits do not light up; or they continue to light up.
e) Wrong figure appears.
f) A certain group of indicators do not light up.
g) The figure of all digits flicker.
continued on next page
Troubleshooting and Testing
Component Test
3-9