Check the large caps if intact and no cracks sa bottom, these tend to be on the expensive side. Check mo na rin sa net if may mga parts na unobtainium or unavailable or expensive to be on the safe side. Some models of output transistors were specially made and are no longer in production, I know sa Pioneer meron unobtanium parts, sa Sansui I am not sure
if nag pro-protect malamang may problem sa power supply, but that does not mean na yung lang ang problem.
IMHO, not unless super cheap or super rare yung item, I would not buy if it does not sound, ok lang yung mga, thumps and pops when you flick switches or adjust th evolume control as these can be easily fixed.