Hitachi C32WD2TN2 TV power on problem

I have a Hitachi C32WD2TN2 TV and it is has a problem at power on. It can take 1 to 20 attempts to get going but it is slowly getting worse. It switches back to standby just as the screen starts to show sings of life. Sometimes it will try to power up again, three or four seconds after failing without the remote being activated. It looks like a power supply ramping but not making it then ramping again on its own (limited knowledge on this front). Once it does power on, it sometimes fails again but comes on easier the next time it is tried. Once it has been on for 5 or 6 minutes it is OK for hours. I found a circuit diagram on the net, but it is very limited and has no PCB layout for component ID etc. Have tried for bad joints without any luck. Has anyone any idea where to start or is there anyway of bypassing the standby circuit as it is never used.