Re: Bush TV22 with TC184 B3 converter.
Ekco describe the diode as a frame pulse shaper, but the main purpose of the diode is to remove any line sync pulses. More complex frame sync circuits were employed in UK made TVs such the two diode circuit shown in the first attachment. This circuit was used in many Pye TV receivers.
The second attachment shows the very simple frame sync coupling employed in many Ferguson receivers. Instead of the usual integrator the frame pulse is supplied to the oscillator by a series capacitor which functions as a differentiator. As simple as the circuit is the interlace is generally good.
DFWB.
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