ROADSTAR SM142B
Manual de Servicio

PICTURE AND COLOUR DEFECTS

No picture Raster OK

Check video out signal at pin 38 of IC101

NO

Check the tuner pin voltages. Check the voltage 3.6-4.6 V at pin 18, 19 of IC101. Check and replace F101, IC101.

YES

Only white raster visible on screen

YES

Check CVBS signal with an oscilloscope. The video signal goes through R103, T104, R154, F104, T105, C150 to pin 40 of IC101

NO

There are flyback lines on the screen

YES

Check Hor. Flyback signal at pin 31 of IC101. Check and replace C129 which is connected to pin 11 of IC101.

NO

There are black drops on the screen.

YES

Check and replace C139

NO

No picture. There is a Red, Green or Blue raster on the screen

NO

Check and replace R167, R206, R118, R136, R137, R135, IC101.