Thorn 3500 chassis
The problem with this set seems to us to be due to an
internal short-circuit in the c.r.t. The raster disappeared,
leaving sound only, and after a few seconds smoke
appeared. This was traced to the c.r.t. final anode connec-
tor, where the plastic covering at the end had melted leaving
a bare resistor whose soldered connection had also melted.
This was resoldered, on the assumption that it had broken,
causing arcing, but the result was a repeat performance.
An internal short-circuit from the c.r.t. final anode is
almost unheard of, but could be proved with a Megger or
ohmmeter. What is much more likely is that the effect is due
to a defective tripler passing a.c.