Hi
One of the 8-301's I have had terrible sync.Would "lock"
on a strong signal but then lose sync etc.
I found from looking at the sync part of the
middle board that a resistor had never been fitted in
manufacture.No resistor,no solder,just the holes in the pcb!
From memory it was around 10K.Fitted it and lock was then great!
Maybe check that and also the resistor values are as the schematic
indicates.
A good test of the sync is to reduce the RF gain(contrast) control and see if the picture keeps locked in.Have a video of mine on youtube here
http://uk.youtube.com/watch?v=StbCuB...e=channel_page
Strangely both of mine have weakish vertical lock if the horizontal hold
is at one extreme or other of the lock in range.Don't know why this is.
Hugh