[FERNSEH]

After reinstalling the chassis into the cabinet I discovered that the line hold control still doesn't alter the frequency of the oscillator. So it's out with the chassis again and back on the bench.
The slider of the line hold control is connected to the line discriminator via a tag strip on a separate line oscillator module which is located above the main chassis. It was found that the screening plate was shorting line hold control to chassis. I've made a spacer to prevent that happening again.
Upon testing the chassis again I found the line hold control still doesn't work.
Another short circuit, this time metallic particles were found in the special line hold control. The control was removed and cleaned up. At last the line hold control works.
A video waveform can be monitored across the diode load of the video detector, but there was evidence of over loading from the signals from the Aurora and my own make standards converter. All the Hunts and waxie decoupling capacitors in the vision AGC system were as expected found to be leaky so the whole lot were replaced.
The result of this action now the overloading is even worse. Now I'll turn my attention to the gated AGC circuit. This consists of an EF80 pentode which functions as the line sync back porch sampler and amplifier. The amplitude of the negative going pulse present at the EF80 anode depends on vision signal amplitude, this is rectified by an EB91 diode and filtered and supplied to the AGC line.

DFWB.