The picture on this set occasionally develops a vertical ” shudder.” Also the picture is subject to
slipping downwards rapidly. This latter fault may
be corrected for varying lengths of time by adjusting the hold control. The valves in the sync separator and frame
circuits have been changed but these same inter- mittent faults recur.
Both faults may appear as soon as the picture comes up after the set is switched on, or after a
long warming -up period.-C. E. Carter (London, W.3).
Whilst a component associated with the sync
separator or frame oscillator may or could be
responsible, we have found that the frame oscillator
transformer is more often at fault in these Ferranti
models. We would, therefore, advise you to first check the small capacitors and resistors associated with the interlace diode and sync separator, and
then change the oscillator transformer.