Yeah, I remember. Well if those were 500 watters, and this amp is a 200 watter, then our 5wpc boomboxes must be headphones only....
I'm sure the new one should work. The problem you have is that the bottomside of the board is not accessible once bolted to the heatsink. Normally, the chip is bolted first, then soldered afterwards. The danger of bolting the chip to the heatsink after it has been soldered is that when torqued down, the leads to the chip could fracture the internal connections or break off inside. That is because the leads are no longer flexible once soldered so it's hard to get an 18 pin chip to conform to mounting irregularities and the physical stress of torquing it down could break something. Not saying that's what happened to your board but it's a possibility and something to always keep in mind when mounting ICs. So for those of you considering replacing an amp module, always remember: First install heatsink. Then after that is secure, do the final soldering to the leads. In your case, that doesn't look to be possible.
I suggest, just excercise care and caution when remounting the new board to that heatsink and ensure that it lays flat on the mounting surface without the need for the fasteners to torque it down. If it does not lay flat on it's own, torquing the fasteners will almost surely crack either the connections or the chip. Also, remember to use sinking compound.
Oh and once you get your new one rocking, send me your old board instead of tossing it, will ya? I'd like to see if it's revivable.
