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PYE 368 CHASSIS
The width reduced by approximately two inches at each
side while the set was being viewed, giving a tall image. To
compensate for the latter effect, I reduced the height. All
valves in the line timebase have been replaced, and adjustment of the preset width controls tried, but without success.
Increasing the brightness control setting increases the size
of the raster, but the picture is then totally out of focus with
a black section in the middle – the same effect occurs when
the set is first switched on. The picture is otherwise very
The lack of width with poor e.h.t. regulation suggests
lack of line drive, while the fact that it occurred suddenly
suggests capacitor trouble. The most likely cause of the
fault is C111 (0.047µF), which couples the line drive to the
line output valve. Otherwise, check the controls, the high –
value resistors in the width circuit (R145/R155/R156), then
suspect the line output transformer.