DECCA 30 CHASSIS

Is there any way of increasing the effect of the pincushion
phase coil L404 on this chassis? At optimum adjustment
there is still a dip in the lines at the top centre of the screen,
while the sides of the raster tilt outwards slightly from the
bottom to the top.
We have often found that better control over the pincushion correction can be achieved by replacing the 104
resistor R48I with a 25Q or 50Q potentiometer. Adjusting
such a potentiometer in conjunction with L404 may well
clear your trouble.