I have this Pro Video Monitor from Sony, it's circuits are believed to be
simular to KVM4121.
Problem is:
All primary voltages are present when loaded with 75 Watt ballast tube and
HOT removed.
I am puzzled though to find out where Hor Drive pulse for Q801 (2SC2688)
originates from. The Hor Drive is totally absent, it looks like that the
unit is forced into SBY by some hidden failure. When main power is turned
on; the frontpanel LED illuminates, When a function is activated the RED LED
flashes momentarily but there is no sign of Hor Drive on my
oscilloscope.....

I have done all the obvious things, checked ESR on Caps, F/R ratios on
Diodes etc but run out of other items to solve this problem.
Any other ideas ???????