THORN TX10 CHASSIS
The original fault with this remote -control set was that the
picture would suddenly revert to monochrome with the
volume going high. At the same time a white line would
streak down the screen. The picture could be reset with the
normal button on the remote control unit. In addition the
picture would dim slightly when subtitles were present.
Now the set cuts out altogether instead, coming on again an
instant later. The symptoms occur mainly just after switch
on, the set settling down once it has warmed up (except for
the odd occasion).
The most likely cause of these troubles is a faulty focus
control unit. If replacing this doesn’t cure the problem,
check for dry -joints at the chopper driver transistor TR721
and the chopper driver transformer 1704. A further
possibility is that the chopper control/trip i.c. is faulty. To
check whether the excess current trip is operating, connect
pin 6 of this i.c. to chassis and run on test.