Re: Lenovo Ideapad 100-15IBD Troubleshooting

I just checked the +3VS line, and there is no short. I do have another motherboard the same model in which I tried to inject voltage into 3VALW and the PCH did not get hot. So in short, this confirms the PCH is the issue. For future guests to read this post, if you do a resistance check from test pad PJ303 to ground and have a short, the processor is most likely the culprit. Thank you Piernov for your help, I really appreciate it.

Re: Lenovo Ideapad 100-15IBD Troubleshooting

Thank you for responding Piernov.
The resistance of the 3VALW line to ground is 22.9 ohms.
The resistance of the 1.05VS line to ground is 188 ohms.
I have injected the voltage without the ac adapter connected.
Also, the smaller die located on the cpu package gets warm. (PCH)

Hello Everybody. I am currently trying to troubleshoot a Lenovo ideapad motherboard that turns on for a moment and shuts off. The motherboard model is: NM-A681 Rev 1.0. The computer shuts off before the bios splash screen can be reached. After probing around, I found there is a short from the 3.3v (Labeled 3VALW in schematic) to ground. I did inspect the board, there are no signs of liquid damage or corrosion. I also tried injecting 3.3 volts and using alcohol to find hot spots, the only thing that got slightly warm was the cpu. I am still new to troubleshooting motherboards, and I was wondering...

Re: New Members - please post your introductions here

Hello. My name is Tristan. Last year I graduated from Pittsburgh Technical college for Electronics Engineering. I am trying to work my way up in the field. I like to tinker, and every day I find new ways how to fix and not fix things. Recently I have been trying to practice soldering surface mount, and I am trying to be proficient at repairing computer motherboards. The place I live in has a black carpet, and it is near impossible to find lost screws.... let alone a surface mount diode smaller than a grain of rice....hahahaha....