Electrolux EI30MH55GB Service Manual - Page 30

EI30MH55GSA EI30MH55GBA EI30MH55GWA SERVICING 1. Precautions for Handling Electronic Components repair all the controls (sensor-related ones included) of This unit uses CMOS LSI in the integral part of the circuits. the touch control panel while keeping it connected to When handling these parts, the following precautions the oven. should be strictly followed. CMOS LSI have extremely B. On some models, the power supply cord between the high impedance at its input and output terminals. For touch control panel and the oven proper is long enough this reason, it is easily influenced by the surrounding that they may be separated from each other. For those high voltage power source, static electricity charge in models, it is possible to check and repair the controls of clothes, etc. and sometimes it is not fully protected by the touch control panel while keeping it apart from the the built-in protection circuit. oven proper; in this case you must short both ends of In order to protect CMOS LSI. the door sensing switch (on PWB) of the touch control 1) When storing and transporting, thoroughly wrap them in panel with a jumper, which activates an operational state aluminium foil. Also wrap all PW boards containing them that is equivalent to the oven door being closed. As for in aluminium foil. the sensor-related controls of the touch control panel, 2) When soldering, ground the technician as shown in the checking them is possible if dummy resistor(s) with figure and use grounded soldering iron and work table. resistance equal to that of the controls are used. (2) Servicing the touch control panel with power supply approx. M ohm 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 2. Servicing of Touch Control Panel activates an operational state that is equivalent to the We describe the procedures to permit servicing of the oven door being closed. Connect an external power touch control panel of the microwave oven and the source to the power input terminal of the touch control precautions you must take when doing so.To perform the panel, then it is possible to check and repair the controls servicing, power to the touch control panel is available of the touch control panel it is also possible to check the either from the power line of the oven itself or from an sensor-related controls of the touch control panel by external power source. using the dummy resistor(s). (1) Servicing the touch control panel with power supply of the oven: 3. Servicing Tools CAUTION: Tools required to service the touch control panel THE HIGH VOLTAGE PARTS OF THE MICROWAVE assembly. OVEN IS STILL LIVE DURING SERVICING AND 1) Soldering iron: 30W PRESENTS A HAZARD. (It is recommended to use a soldering iron with a grounding Therefore, before checking the performance of the touch terminal.) control panel, 2) Oscilloscope: Single beam, frequency range: DC-10MHz 1) Disconnect the power supply cord, and then remove type or more advanced model. outer case. 3) Others: Hand tools 2) Open the door and block it open. 3) Discharge high voltage capacitor. 4. Other Precautions 4) Disconnect the leads to the primary of the power 1) Before turning on the power source of the control unit, transformer. remove the aluminium foil applied for preventing static 5) Ensure that these leads remain isolated from other electricity. components and oven chassis by using insulation 2) Connect the connectors of the key unit to the control unit tape. being sure that the lead wires are not twisted. 6) After that procedure, re-connect the power supply 3) After aluminium foil is removed, be careful that abnormal cord. voltage due to static electricity etc. is not applied to the After checking the performance of the touch control input or output terminals. panel, 4) Attach connectors, electrolytic capacitors, etc. to PWB, 1) Disconnect the power supply cord. making sure that all connections are tight. 2) Open the door and block it open. 5) Be sure to use specified components where high precision 3) Re-connect the leads to the primary of the inverter is required. 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 30