File name TQ2092 TV COLOR.pdf
CONTENTS Safety precautions... 1 Alignment instructions ... 2 Working principle analysis of the unit...8 Block diagram... 9 IC block diagram...10 Wiring diagram ... 15 Troubleshooting... 16 Schematic diagram ... 18 APPENDIX-A: Main assembly list APPENDIX-B: Exploded view
Note: This service manual is only for professional service personnel's reference. Before servicing the unit, please read the following items carefully.
1. X-RAY radiation precaution
1.1 Excessive voltage will cause harmful X-ray. To avoid this radiation hazard, the high voltage should fall within the limitation. The appliance works at AC 120V, 60Hz. The high voltage of zero beam current (brightness is min) should be within 30kV on condition that the main power voltage is 110V(13", 20"), 130V(24") and 135V(37"). And it should not exceed 33kV in any condition. When servicing, please refer to the HIGH VOLTAGE CHECK procedure this service manual before check the high voltage and the high voltage meter should be reliable and accurate. * Keep the main power voltage at 110V(13", 20"), 130V(24") and 135V(37") when checking the high voltage. 1.2 The primary source of X-RAY RADIATION is the CRT. The CRT of this TV set have gotten the approval of safety authentication inspection. The replacement CRT should be exactly the same type and specification CRT which has gotten a similar safety approval, and check the high voltage according to the HIGH VOLTAGE CHECK procedure.
2. Safety precaution
a. Since the power supply circuit of this receiver is directly connected to the AC power line, an isolation transformer is necessary during dynamic service to avoid possible shock hazard. b. Always discharge the graphite layer conductor when moving the CRT. c. Disconnect the power cord before replacing parts. d. When replacing high-power resistor, keep the resistor 10 mm away from the circuit board.
3. Component safety precaution
Many electrical and mechanical parts in the chassis have special safety-related characteristics. These characteristics are often passed unnoticed by a visual inspection. Replacement parts which have these special safety characteristics are identified in this manual and its supplement electrical components having such features are shaded or marked by on the schematic diagram and the parts list. Befo