PYE 741 CHASSIS
The screen occasionally goes very bright, though it’s still
controllable – if the brightness control is turned right back
with the fault present, there’s a good monochrome picture
but no colour. The trouble is intermittent, but when it
appears it lasts for an hour or so. The fault is definitely on
the decoder board, since a replacement panel clears it. All
the i.c.s have been replaced without improving matters.
It’s possible that the burst gate control RV325 is
incorrectly set: as a guide, its wiper point usually faces the
nearest end of R328. Alternatively, lack of line pulses via
the adjacent two -pin plug will cause the same effect.