I have the above lcd that is more or less dead.It's as if the 17pw15-9 power pcb standby stages are being suppressed,but if I discon.PL803 TO THE 17MB22-2 I get most of the voltages back.I now have the 12v to ic825[Q809],the 5V and 3V3 are up . the 24v is now ok along with a 12v & 30v lines,but still no led. I don't believe the main board is dragging things down and have replaced the two 4700/6.3v caps inthe standby circuit.
Any clues mates , tv john.
PS Thanks to Highlandelectrix for the plug voltages(probably with some variations).