Bush LY2211wcw intermittent fault

[johnboy183]

Hi,
I picked up one of these quite a while ago as stuck in standby (ie solid red light and no response to remote or buttons). Having replaced all of the powerboard caps as a matter of course without success I was almost going to give up on it but when I reassembeled it it all sprung to life and continued to work (all functions) for some 6 weeks or so (on for extended periods every day and switched on and off many times a day). A couple of days ago I tried to switch on and back to the original fault ie solid red light and no functions. The only clue I have is that when it is working the BL-ON lead between main and power board shows 4.9 volts and 0 volts when it fails. I have tried a different TFT panel to eliminate that and checked out the transistors and transformwr solder joints and cant even find a dry joint anywhere (which could have explained it)
Any ideas to point me towards would be very greatly appreciated before I tear my hair out completely!
regards
John