1 Sep
2015
1 Sep
'15
7:59 a.m.
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. 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