Hey Meller, I've done that before. Actually, just recently. I had to buy a new RX18 board to have sounds again.

Replacing the amp and replacing the big carbon coated 2-5 watt resistor didn't solve the issue. Had to remove the amp completely, because the amp gets so hot, that it began to warp the corner of the RX18 casing that the amp is directly under. I suspect it's one of the chip resistors adjacent to the amp. I found that it was becoming more trouble than it was worth to fix the board.....so I just sprung for a $22 dollar replacement.

I believe that amp getting that hot is a safety issue, so I removed the amp completely from the board and intend on using the RX18 board with an aftermarket sound module since the board still works.