A1286 820-3330-B 1SNS IPBR liquid damage repair

Hello everybody.

I'm trying to repair this mac which had liquid damage.

I already cleaned the logic board with isopropyl alcohol, but it still doesn't work properly.

1)I need to keep pressed power button for more than 5 seconds to turn it on

2)Apple Hardware Test returns 1SNS/IPBR error

3)System is terribly slow (lots of cpu used).

4)Note: once I physically detach the battery, power button apart the system run smoothly.

I bet there is something wrong with the battery circuit on the logic board.

I sent it to an unofficial but supposed-to-be expert repair centre here in Italy, and they told me that the logic board is too damaged and there is nothing to do. They already tried to swap battery but the problem persists.

Actually, in my specific case "being too damaged for being repaired" sounds a bit strange to me.

Unfortunately I'm just a computer technician but don't have equipment neither Knowles to change bga and smd chips.

Any suggestion / help (board changing apart?) :D

Thanks!