Mainboard problem Laptop Lenovo Ideapad 3 15ada05

[micsa84]

Hello! I have a problem with a mainboard from a Lenovo Ideapad 3 15ada05.
The problem is that the cooling fan is always on full speed, It doesn't recognize the battery and it is not charging it and the keyboard has only partial functionality, many of the keys don't work.
I tried a new bios update but that didn't changed anything.
What could be the problem with it?

[mcplslg123]

Re: Mainboard problem Laptop Lenovo Ideapad 3 15ada05

You didnt tell us whether there is display or not? Keyboard and battery often fails-so should be tested with new components first. Fan spinning fast may be due to me region in bios.

[micsa84]

Re: Mainboard problem Laptop Lenovo Ideapad 3 15ada05

Thanks for the reply. The mainboard has display, the bios was reflashed with a good working dump. It is a mainboard related problem, with another board everything works great. Can it be a CPU problem?

[SMDFlea]

Re: Mainboard problem Laptop Lenovo Ideapad 3 15ada05

Have you checked around the EC chip for corrosion.

[Sephir0th]

Re: Mainboard problem Laptop Lenovo Ideapad 3 15ada05

Most common reasons, are a dead keyboard, a dead battery and a issue in the fan circuit (or a bad fan). Just saying.
Typical advise is to replace suspects first and troubleshoot afterwards if it doesn't solve the issue

[micsa84]

Re: Mainboard problem Laptop Lenovo Ideapad 3 15ada05

I looked more closely under a microscope and the board is a mess. The mainboard from my computer had some ddr related problems. I ordered a "new" mainboard from aliexpress and the one that i got is a complete disaster. It has some missing components, i think the EC was changed and it is not welded properly. In the meantime I reflowed the ram on my board and everything works fine. I opened a dispute and sending this board back. I was just curious what can cause this symptoms cause the board was working except that fan problem, keyboard and the battery. Thank you all for the help and support!