Electrolux EI30MH55GBA, Technical & Service Manual

Page: 42 / 70

Component Teardown
4-2
1. Precautions for Handling Electronic
Components
This unit uses CMOS LSI in the integral part of
the circuits. When handling these parts, the
following precautions should be strictly followed.
CMOS LSI have extremely high impedance at its
input and output terminals. For this reason, it is
easily influenced by the surrounding high voltage
power source, static electricity charge in clothes,
etc. and sometimes it is not fully protected by
the built-in protection circuit.
In order to protect CMOS LSI.
1) When storing and transporting, thoroughly
wrap them in aluminum foil. Also wrap all PW
boards containing them in aluminum foil.
2) When soldering, ground the technician as
shown in the figure and use grounded soldering
iron and work table.
2. Servicing of Touch Control Panel
We describe the procedures to permit servicing of
the touch control panel of the microwave oven
and the precautions you must take when doing
so. To perform the servicing, power to the touch
control panel is available either from the power
line of the oven itself or from an external power
source.
(1) Servicing the touch control panel with power
supply of the oven:
CAUTION:
THE HIGH VOLTAGE PARTS OF THE MICROWAVE
OVEN IS STILL LIVE DURING SERVICING AND
PRESENTS A HAZARD.
Therefore, before checking the performance of the
touch control panel,
1) Disconnect the power supply cord, and then
remove outer case.
2) Open the door and block it open.
3) Disconnect the leads to the primary of the
power transformer.
4) Ensure that these leads remain isolated from
other components and oven chassis by using
insulation tape.
5) After that procedure, re-connect the power
supply cord.
After checking the performance of the touch control
panel,
1) Disconnect the power supply cord.
2) Open the door and block it open.
3) Re-connect the leads to the primary of the
inverter unit.
4) Re-install the outer case (cabinet).
5) Re-connect the power supply cord after the
outer case is installed.
6) Run the oven and check all functions.
A. On some models, the power supply cord
between the touch control panel and the oven
itself is so short that the two can’t be separated.
For those models, check and repair all the
controls (sensor-related ones included) of the
touch control panel while keeping it connected
to the oven.
B. On some models, the power supply cord between
the touch control panel and the oven proper is
long enough that they may be separated from
each other. For those models, it is possible to
check and repair the controls of the touch control
panel while keeping it apart from the oven proper;
in this case you must short both ends of the door
sensing switch (on PWB) of the touch control
panel with a jumper, which activates an opera-
tional state that is equivalent to the oven door
being closed. As for the sensor related controls of
the touch control panel, checking them is possible
if dummy resistor(s) with resistance equal to that
of the controls are used.
(2) Servicing the touch control panel with power sup-
ply from an external power source:
Disconnect the touch control panel completely
from the oven proper, and short both ends of the
door sensing switch (on PWB) of the touch
control panel, which activates an operational state
that is equivalent to the oven door being closed.
Connect an external power source to the power
input terminal of the touch control panel, then it is
possible to check and repair the controls of the
touch control panel it is also possible to check the
sensor-related controls of the touch control panel
by using the dummy resistor(s).
Servicing
approx. 1M ohm