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Trace the line voltage in as far as you can. Past the fuses there will be some filtering (MOV, couple of small caps, common mode coil), a thermistor (current limiter), and then a bridge. After the bridge it's DC. You should see a few hundred volts or so on big electrolytic filter caps in this part of the circuit. This will go to a MOSFET screwed to a heatsink, often the source of the trouble, they can fail open or short.
Could we possibly get a tad bit more information on this? When you say dead, what are the power supplies' symptoms? are you getting anything at all from any of the switching supplies' various outputs?
had a check at the set today,ac present,dc out of bridge there but going amiss into q65 transistor couple of wirewound resisistors there,any help with diagram or advice,cheers STUARTY
Do you not see the voltage at the transistor? This is actually a good sign, could be a simple-stupid break somewhere. Find out where that high voltage stops. Take a close look at the pins of the high-frequency power transformer the transistor is connected to, check the solder junctions, might be a broken pin or pad there.
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