R - 5 2 0 L K

R-520LW

TOUCH CONTROL PANEL SERVICING

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 aluminium foil. Also wrap all PW boards containing them in aluminium foil.

2)When soldering, ground the technician as shown in the figure and use grounded soldering iron and work

approx. 1M ohm

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 TRANSFORMER 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)Discharge high voltage capacitor.

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.

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 power transformer.

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 operational 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 supply 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).

3.Servicing Tools

Tools required to service the touch control panel assembly.

1)Soldering iron: 30W

(It is recommended to use a soldering iron with a grounding terminal.)

2)Oscilloscope:Single beam, frequency range:DC-10MHz type or more advanced model.

3)Others: Hand tools

4. Other Precautions

1)Before turning on the power source of the control unit, remove the aluminium foil applied for preventing static electricity.

2)Connect the connectors of the key unit to the control unit being sure that the lead wires are not twisted.

3)After aluminium foil is removed, be careful that abnormal voltage due to static electricity etc. is not applied to the input or output terminals.

4)Attach connectors, electrolytic capacitors, etc. to PWB, making sure that all connections are tight.

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Sharp R-520LW, R-520LK Touch Control Panel Servicing, Servicing of Touch Control Panel, Servicing Tools, Other Precautions

R-520LK, R-520LW specifications

The Sharp R-520LW and R-520LK are innovative microwave ovens that combine advanced technology with user-friendly features to enhance cooking experiences. Designed with modern kitchens in mind, these models embody efficiency, precision, and versatility.

One of the defining characteristics of both the R-520LW and R-520LK is their powerful 900-watt output, which allows for speedy cooking and reheating. This high wattage ensures that food is cooked evenly and retains its moisture, preventing the common issue of dry or unevenly heated meals. Furthermore, the inclusion of multiple cooking power levels provides users with flexibility, making it easy to select the ideal setting for various types of food.

Both models feature Sharp's signature Inverter Technology. Unlike traditional microwaves that use a turn-on and turn-off cycling method, inverter technology delivers a steady stream of cooking power. This results in more consistent heating, allowing delicate foods such as fish or custards to be cooked perfectly without overcooking the edges. This technology not only enhances the quality of cooked food but also improves the overall efficiency of the microwave.

The R-520LW and R-520LK come equipped with a variety of auto-cook settings that cater to different culinary needs. From popcorn to frozen vegetables, these pre-programmed settings allow users to prepare meals with just a touch of a button, making cooking uncomplicated for all skill levels. The large, user-friendly control panel features intuitive buttons and a digital display, ensuring effortless operation and visibility.

In terms of design, the R-520LW boasts a sleek white finish, while the R-520LK offers a modern black aesthetic. Both models are compact yet spacious, with a generous interior capacity that can accommodate a range of dish sizes. The turntable feature further enhances cooking efficiency by ensuring even cooking all around.

Cleaning and maintaining the R-520LW and R-520LK is a breeze, thanks to their easy-to-wipe surfaces and the interior's cavity that can be easily accessed. The durable construction of these microwaves means they are designed to withstand the rigors of daily use.

In summary, the Sharp R-520LW and R-520LK microwave ovens stand out with their advanced features, such as inverter technology and pre-programmed cooking settings, making them excellent choices for anyone looking to streamline their kitchen tasks. Their stylish designs and user-friendly interfaces further enhance their appeal, making them valuable additions to any modern home.