[1100 man]

Hi David & John,
Thanks for your suggestions and information on circuit operation. I did look at the waveform on the PCL82 triode anode but was not entirely sure what I was expecting to see! As the height control is increased to allow the PCL to work with 55V, the sharp bit at the start of the forward scan disappears. With correct picture height and only 20V, the rest of the scan is remarkably linear!
Could a faulty output TX or coils cause this excess height? Assuming the component values printed in the R&TV book are correct, mine correspond to them.

Presumably, resistors across the scan coils might damp out that initial ring- if that is what it is?

Out of interest, some circuits use a two valve multivibrator, and some can manage with only a single triode (my Pilot where they have done everything to reduce the valve count). Are there advantages with the two valve arrangement?
The set has now been run for many hours over the last few weeks and I've actually watched it for an evening's entertainment. That's when I decided that I needed to fix the frame fault- even though it is pretty minor!
The repaired LOPT is working extremely well and runs nice and cool even after several hours of use so that was a worthwhile exercise.
I won't have a chance to look at it again until the weekend.
Many thanks
Nick