THORN 8000 CHASSIS
The set lost its colour. An exchange i.f./chroma/video panel
was fitted and the set worked well for about three weeks.
Then the colour started to come and go – sometimes disappearing for a few minutes, at other times for an hour or so.First check the 33kS2 resistor R404 on the timebase panel
– it supplies the burst gating pulses, and has a habit of going
high -resistance. If this is o.k., turn to the decoder section.
Try slight adjustment of the burst gate timing control R151,
in an anti -clockwise direction. If this fails and you are sure
there are no dry joints or board faults present, replace the
d.c. amplifier transistor VT110 and then set up the a.p.c.
loop as described in the manual.