When first switched on the picture rolls up or down and adjustment of the vertical hold control
is necessary to lock the picture. During an evening’s viewing the fault will recur and adjustment
is again necessary. I have replaced the two ECL80’s, V14 and V15. -R. Saunders (Rainhill, Liverpool).
Test the components which are connected
between the sync separator valve and the frame oscillator, for your remarks indieitte that the frame
sync pulses are attenuated due to a component fault. Also check the 0A61 interlace filter diode
on pin 1 circuit of the ECL80 frame valve.