I recently replaced the jack on my friend's ATK 800 because it was loose. With the new jack, it was impossible to plug the 1/4" plug into it fully. I used a screwdriver to see what was inside and now I can plug the cord into it. Problem is that when I inserted the screwdriver, I must have shorted the 9V from the battery to the input of the preamp. The sound was fuzzy. I replaced the quad op-amp chip (TLC2264C). The sound is different, but it's still fuzzy. Can someone point me to where I can find a schematic of the printed circuit board? How about where I can buy just the circuit board. Ibanez doesn't sell just the board. You have to buy the entire assembly which includes all the switches and volume controls.