[FERNSEH]

The attachment shows the sync separator and frame timebase circuit of the Pye V2 and VT2. A negative going sawtooth waveform is developed across C45(0.25mfd). Timebase frequency is determined by C45 and 390Kohm resistor R60. Bottom end of the frame hold control is returned to the cathode of the video amplifier valve. The 12mfd electrolytic capacitor C44 decouples the HT supply to the frame TB and sync separator and also the screen grid supply to the screen grid of the video amplifier valve V4. Low capacity in this capacitor will cause all sorts of funny sync faults.
It's possible that C45 is connected to the cathode of V14 to improve the linearity of the sawtooth developed across the capacitor, the parabolic waveform across the cathode bypass capacitor C48 is used for this purpose.
Interlace diode V8B will only conduct on the negative going integrated frame pulses. A leak in frame sync coupling capacitor will C43 cause weak frame hold.
A leak in coupling capacitor C46 can cause cramping at the top of the picture, the negative going waveform biases the output valve to near cut-off.

DFWB.