Used samsumng hcp4752wx/xaa is showing tri...

Not too familiar with this exact model but am very familiar with Samsung DLP. If this is a Rear Projection (3 CRT's R.G.B.) it is surely the convergence chips ($12 each X 3). If this is a DLP (Color Wheel @ 7000rpm) this is not good news as a DMD board for Samsung DLP is around $400 (not retail either, warranty part price).