AIWA TVA20S2
Service Manual

NOTICES BEFORE REPAIRING

To make the best use of this equipment, make sure to obey the following items when repairing (or mending).
1. Do not damage or melt the tunicate of the leading wire on the AC1 side, including the power supply cord. 2. Do not soil or stain the letters on the spec. inscription plates, notice labels, fuse labels, etc. 3. When repairing the part extracted from the conducted side of the board pattern, fix it firmly with applying bond to the pattern and the part. 4. Restore the following items after repairing. 1) Conditions of soldering of the wires (especially, the distance on the AC1 side). 2) Conditions of wiring, bundling of wires, etc. 3) Types of the wries. 4) Attachment conditions of all types of the insulation. 5. After repairing, always measure the insulation resistance and perform the voltage-withstand test (See Fig-1). 1) The insulation resistance must be 7.0 to 9.5 M� when applying 500V per second. 2) In the voltage withstand test, apply 3 kV for 1 or more minutes and check that the GO lamp lights. * * * * Breaking current set to 6 mA. Connect the safety checker as shown in Fig-1, then measure the resistance and perform the test. Do not touch the equipment during testing. For details of the safety checker, refer to the supplied Operation manual. Fig-1 Insulation resistance: 7.0 to 9.5 M� (500 V/s) Voltage-withstand: 3 kV for 1 or more minutes

Safety checker (Model 7110, etc.)

Earth cable

AC cable

Connect the earth cable to the outside metal part terminal.

When servicing and checking on the TV, note the followings.
1. Keep the notices. As for the places which need special attentions, they are indicated with labels or seals on the cabinet, chassis and parts. Make sure to keep the indications and notices in the operation manual. 2. Avoid an electric shock. There is a high voltage part inside. Avoid an electric shock while the electric current is flowing. 3. Use the designated parts. The parts in this equipment have the specific characteristics of incombustibility and withstand voltage for safety. Therefore, use a part which has the same character as the replaced part. Especially as to the important parts for safety which is indicated in the circuit diagram or the table of parts with a ! mark, the designated parts must be used. 4. Put parts and wires in the original position after assembling or wiring. There are parts which use the insulation material such as a tube or tape for safety, or which are assembled so that these parts do not make contact with the printed board. The inside wiring is designed not to get close to the pyrogenic parts and high voltage parts. Therefore, put these parts in the original positions. 5. Take care of the cathode-ray tube. By setting an explosion-proof cathode-ray tube in this equipment, safety is secured against implosion. However, when removing it or servicing from the back, it gives out shock that is dangerous. Take enough care to deal with it. 6. Avoid an X-ray. Safety is secured against an X-ray by giving considerations to the cathode-ray tube and the high voltage peripheral circuit, etc. Therefore, when repairing the high voltage peripheral circuit, use the designated parts and do not change the circuit. Repairing, except indicates, causes rising of high voltage, and the cathode-ray tube emits an X-ray. 7. Perform a safety check after servicing. Confirm that the screws, parts and wiring which were removed in order to service are put in the original positions, or whether there are deteriorated portions around the places serviced.

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