Re:- "which in turn will cause the battery to become warm", this of course should be battery or "casing" adjacent to whatever component is overheating.

Farid -Although it could well be the main power circuit board at fault its still not necessarily 100% guaranteed that it is this, as the symptom you mention only indicates that battery is running into a short circuit (or partial one) causing excessive power consumption which in turn will cause the battery to become warm, so any area of the internal circuitry could be responsible for this and it really has to be looked at before anything is ordered.