Unhappy [Q] htc pure or Touch Diamond2 circuit diagram

I have a HTC pure mobile.it's brightness is very low.some times it's brightness going high and low.my technician said that problem is voltage to display on main board.I have replace a new display.but problem is same.now we need circuit diagram for check lcd backlight voltage to fix it.

please can anyone give me a circuit diagram for htc pure or Touch Diamond2 or have a other idea to fix it?

its is big help for me to fix it.

I am waiting for answer ASAP.