EKCO T348: Raster Ripple

The symptom of the fault on one of these receivers was distortion of the raster which gave it the appearance of a modulation envelope. As there were two complete sine waves, the raster was being modulated at a frequency of 20kHZ.

After considerable time and trouble the fault was traced to a broken strip which normally holds together the two halves of the ferrite core on which the scanning coils are mounted