Chosen Solution
Hello, diagnosing a strange issue here. Laptop works fine plugged in. When disconnected from ac adapter the laptop works but the screen goes very dark as in the backlight just quits. System still works fine. Connect the adapter back and the backlight Comes on. Tried all windows settings but this issue happens in bios as well. The only thing I can think of is the battery is at fault as I read that in dell XPS series the backlight power is fed straight from the battery. Currently waiting for a new battery. Anyone else have similar issue?
It’s not the battery issue or the software. It’s the main bord if the display, very common issue with Asus and Acer Touch Screen Display. If you want to fix this you have to replace the diode and the coil from the display main board. Some times the led driver IC or the resistor from the IC
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.
