Dell LA-9981P laptop cannot be powered on for repair

Dell lA-9981P laptop cannot be powered on for repair

Machine model: Dell LA-9981P

Malfunction: Notebook Won’t Turn On

Maintenance process: take the battery Connect the power supply source 0.003 Switch without response no power on.

Dell LA-9981P laptop cannot be powered on for repair Figure 1.

I’m afraid the CPU will hang up. Let’s see if standby 3V5V exists first.

Dell LA-9981P laptop cannot be powered on for repair Figure 2.

Dell LA-9981P laptop cannot be powered on for repair Figure 3.

Since 3V5V depends on the EC conditions, because it is a single CPU, we should look at EC first. Open the drawing and find Switch into EC 114 pin. The measurement is only 1.5V. How can it be only 1.5 V?

Dell LA-9981P laptop cannot be powered on for repair Figure 4.

Dell LA-9981P laptop cannot be powered on for repair Figure 5.

Switch has obvious current of change, so let’s leave it alone, and see if the adapter detection and LID at the back are normal. It is found that the measurement adapter is 3.3, and the LID is only 1.5V That should be the problem!

Dell LA-9981P laptop cannot be powered on for repair Figure 6.

Seeing that it is connected with a 10K resistor, the drawing shows that it is a 10k pull-up resistor, and the measurement result is 3.3 on one side and 1.5 on the other, so the problem should be on this resistor.

Dell LA-9981P laptop cannot be powered on for repair Figure 7.

Dell LA-9981P laptop cannot be powered on for repair Figure 8.

In order to test, I connected the current directly with tweezers, and it should be that this resistor is damaged.

Dell LA-9981P laptop cannot be powered on for repair Figure 9.

Dell LA-9981P laptop cannot be powered on for repair Figure 10.

switch won’t be powered on after replacement. Unplug the memory, power it on, and then look at it and find that the current runs to 0.4, which proves that the memory has started to run.

Dell LA-9981P laptop cannot be powered on for repair Figure 11.

It’s okay to test the motherboard VCC again. I think I didn’t read the program. I decisively downloaded a BIOS from the forum. After brushing it, the current has obvious current of change. Connect the screen line booting up, and the maintenance is over.