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Television 1 Jess UEAB2006 AFT and remote control Circuits.

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Presentation on theme: "Television 1 Jess UEAB2006 AFT and remote control Circuits."— Presentation transcript:

1 Television 1 Jess Role @ UEAB2006 AFT and remote control Circuits

2 Television 1 Jess Role @ UEAB2006 Importance of AFC  Receivers that have provisions for remote tinning have no provision for remote fine tuning  Color receivers that have provisions for remote tuning to obtain the best color reproduction  Many customers found it difficult to adjust the manual fine tuning control property  A very slight drift in the frequency of the tuner oscillator causes a loss of color picture quality

3 Television 1 Jess Role @ UEAB2006 AFT Section

4 Television 1 Jess Role @ UEAB2006 Troubleshooting AFT circuits  Weak or no AFT performance  No picture no sound raster ok  Large tuning error  Moment to moment picture variations

5 Television 1 Jess Role @ UEAB2006 Ultrasound remote control

6 Television 1 Jess Role @ UEAB2006 Causes of AFT problems  A defective transistor or associated circuits  A defective transformer  defective IC or associated circuits such as an open coil  Misalignment of the AFT tuned circuits  Incorrect power supply voltage  Defective varactor  Incorect varactor voltage

7 Television 1 Jess Role @ UEAB2006 AFT circuit that uses dc amplifier to drive the varactor

8 Television 1 Jess Role @ UEAB2006 Large tuning error on channels that originates form the varactor  DC amplifier balance change caused by the change in resistor anywhere in the DC amplifier  Defective varactor

9 Television 1 Jess Role @ UEAB2006 Remote control Capability  Change channel  Adjust volume  Adjust picture  Adjust contrast  Adjust sharpness  Sound quality adjustment  Power switch

10 Television 1 Jess Role @ UEAB2006 Remote controls  Ultrasonic Transmitter –Acoustic transmitter –Function by tune signals from receiver to transmitter

11 Television 1 Jess Role @ UEAB2006 Ultrasound remote control

12 Television 1 Jess Role @ UEAB2006 Kinds of remote control faults  Weak intensive response on all function  Dead all function  Dead on some function but not all

13 Television 1 Jess Role @ UEAB2006 Electronic memory remote control  Producing ultrasonic sound through electronic circuit controlled system.

14 Television 1 Jess Role @ UEAB2006 Three tone remote control

15 Television 1 Jess Role @ UEAB2006 Infrared system  Using invisible infrared signal  Digitally modulated infrared signal 42 KHz sensed by infrared diodes.

16 Television 1 Jess Role @ UEAB2006 Infrared remote control

17 Television 1 Jess Role @ UEAB2006

18 AFT discriminator circuit

19 Television 1 Jess Role @ UEAB2006 AFT Circuit

20 Television 1 Jess Role @ UEAB2006

21 Receiver

22 Transmitter

23 Multifunction Remote Control


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