11AK19 free download

File name CHASSIS 11AK19.pdf

1 DO NOT CHANGE ANY MODULE UNLESS THE SET IS SWITCH OFF The mains supply side of the switch mode power supply transformer is live. Use an isolating transformer. The receivers fulfill completely the safety requirements. Safety precautions: Servicing of this TV should only be carried out by a qualified person. - Components marked with the warning symbol on the circuit diagram are critical for safety and must only be replaced with an identical component. - Power resistor and fusable resistors must be mounted in an identical manner to the original component. - When servicing this TV, check that the EHT does not exceed 26kV. TV Set switched off: Make short-circuit between HV-CRT clip and CRT ground layer. Short C804 (150mF) before changing IC802 or other components in primary side of SMPS. Measurements: Voltage readings and oscilloscope traces are measured under following conditions. Antenna signal 60dB from colourbar generator. (100% white, 75% colour saturation) Brightness, contrast, colour set for a normal picture. Mains supply, 220VAC, 50Hz. PERI-TV SOCKET 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 Audio right output Audio right input Audio left output Ground AF Ground Blue Audio left input Blue input AV switching input Ground Green Green input Ground Red Ground Blanking Red input Blanking input Ground CVS output Ground CVS input CVS output CVS input Ground SCART 1 (SC050) 0.5Vrms / 1K 0.5Vrms / 10K 0.5Vrms / 1K 0.5Vrms / 10K 0.7Vpp / 75ohm 0-12VDC /10K 0.7Vpp / 75ohm 0.7Vpp / 75ohm 0-0.4VDC, 1-3VDC / 75ohm 1Vpp / 75ohm 1Vpp / 75ohm 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 Audio right output Audio right input Audio left output Ground AF Ground Blue Audio left input Blue input AV switching input Ground Green Ground Red Ground Blanking Ground CVS output Ground CVS input CVS output CVS input Ground SCART 2 (SC051) 0.5Vrms / 1K 0.5Vrms / 10K 0.5Vrms / 1K 0.5Vrms / 10K 0.7Vpp / 75ohm 0-12VDC /10K 1Vpp / 75ohm 1Vpp / 75ohm * * ALL WIRES TO FRONT PANEL & LOUD SPEAKERS MUST BE ZIP-TIED TOGETHER AFTER ANY KIND OF REPAIREMENT 1. INTRODUCTION 11AK19 is a 90ш and 110ш chassis capable of driving 20-21,24,25,28-29,32,33 tubes at appropriate currents. The chassis is capable of working in both PAL and SECAM. The sound system is capable of giving 6watts RMS output into a load of 8ohms. One 8 page simple TELETEXT, TOPTEXT and FASTEXT is provided. The chassis is equipped with 21-pin scart connectors which can accept via scart the SVHS format from VCRs so equipped. 2. SMALL SIGNAL PART WITH TDA884X The TDA8840/8842/8844 combine all small signal functions required for a colour TV receiver, except tuning. 2.1. Vision IF amplifier The IF-amplifier contains 3 AC-coupled control stages with a total gain control range which is higher than 66dB. The sensitivity of the circuit is comparable with that of modern IF-IC s. The video signal is demodulated by means of a PLL carrier regenerator. This circuit contains a frequency detector and a p