Can anyone advise me im an electronics engineer by trade, usually dont look at things like this and normally repair tv's lcd and plasma etc etc , but yest a friend brought me his xbox 360 the machine had three red lights RROD syndrome i am aware of the fault and how it is curred, i done the x-clamp fix the indepth one so that went really well but on doing this i notice that someone else had looked at the unit prior to myself as it had been chipped for one and for two the left xclamp was half taken off and a substancial scratch was obvious on the PCB, on knowing a lot about PCB manufacture i would only asume the pcb itself is a multi layer board maybe two or three layer so would deem this PCB b.e.r, (beyond economic repair)it would be possible to repair the top layer with much dificulity which i did anyhow.
But unfortunately still not repaired the fault is there any known way to replace the mainboard and fit the lads original dvd drive coz i hear the serial numbers found in the dvd rom are criticle can anyone point me in the right direction any help would be fantastic

kindest regards in advance stu pot