> > You need to trace on from pin 8 to transistors on the main board, > > right up to the flyback transformer. > > > I did. The 18KHz signal is present when it enters the board from the > wire, it is also present on the collector of the following 2 > transistors (the TR21 and TR22 which are part of the brightness > limiter and horizontal driver respectively), also at the output of the > T501 transformer and at the collector of the TR23 transistor (which is > labeled as Horizontal out). I then traced at every pin until the > flyback transformer input (pin 4). According to the schematic and the > board it seems that is the signal path from the moment it enters the > logic board until it reaches the flyback transformer.
What do you see on the collector of TR23, which should be a small power transitor (TO220 package I think). If it's working properly there would be some very high voltage spikes (kV) there, but under these conditions probably not. What is the average DC voltage there? > However the flyback transformer is definitely not outputting the > voltages it is supposed to, as the manual tells me to measure 56.8V at > the cathode of diode D504 which is basically connected to the output > pin 6 of the flyback transformer and I only measure few mV. > > Could a winding of the FBT be burned somehow? Could be, You have a schematic, the flyback windings should be very low resistances. Check them with the ohmmeter. -tony
