GEC 2040

I’m in the process of renovating one of these single -standard
hybrid colour receivers. The first fault was no results, with
the mains fuse blown. This turned out to be due to a faulty
thermal cut-out in the line output stage and a defective line
output transformer. Replacing these components restored
results of sorts, but the line oscillator was running three
times too fast – the core was missing from the line oscillator
coil L501. Having obtained a just about acceptable picture,
I found that on increasing the setting of the contrast control
any highlights are accompanied by a kind of faint magenta
or greenish bar, running horizontally. The video valves
(PL802 and the three PCL84s) and the associated electrolytics
have been replaced, but the fault persists – its
objectionable on all but the least contrasted scenes and is
present with the colour turned on or off, also with each of
the first anode presets turned off.
Since you’ve changed the likely components in the video
area, it could be that there’s a small low -resistance area on
the board. It would be advisable to check the electrolytics in
the power supply, especially C58 (2,000,0) and C59
(1,000µF), the 20V supply smoothing and reservoir
capacitors.