Original post by: arbaman ,
If you’re up for testing you can probe battery pins and see if you have the 8v and the 3.4v power lines. If you do you can rule out I/O board and you’ll know main power lines are up and running. If you have no voltages it would be worth to try and replace the I/O board, such repair attempt would be quite cheap and easy to perform. In case of failure a component level troubleshooting or board replacement would be the two alternatives.