Original post by: dancer1000 ,
I've done some research and the charging circuit is supposed to supply 12v to charge the battery. With the battery out, I have 12v at the charging circuit mosfet but as soon I connect the battery, it drops to 8v. That makes me suspect the battery is faulty but it can be also something in the panel circuit. At the monitor connector I have 19v with charger, and 8v with battery. I used a power supply to inject 12v with the battery connected and the screen backlight started working. If I take out the 12v supply, it drops again to 8v and turn off the backlight. As I see it, a “faulty" battery could be forcing the 12v charging circuit to drop to the battery voltage. With the battery connected and the power supply at 12v at the battery connector, It draws around 3,5amps only at that point meaning either the battery is faulty or I have a short somewhere else, probably at the panel circuit. It's too much amps….if I solve this problem I'll post the solution here.