Lenovo Ideapad 5 15ARE05 - no post

[johnbeton]

Hello,

I have Ideapad 5 15ARE05 which turns on, but no post or display. No reaction on capslock or numlock.
All voltages seem to be fine on all the coils. I thought bios could be corrupt, but flashed with several versions from this forum with no succes.
CPU gets hot fast, and has only onboard memory, no ram slot.
I'm thinking bad cpu/gpu or ram, but no possibility to test. Or could this be a problem with the EC ?

Thanks

[johnbeton]

Ok, found out PLT_RST# is missing, so further looking in to that.

[johnbeton]

got it fixed, flashed bios again with a TL-866 II programmer instead of CH341A. System works now.
Which is weird, with CH341A read, write and verify would complete without error

[mon2]

Thanks. Good to know. Recently purchased the T56 model. It kicks. The effort is in the software algorithms and their updates. You pay, you receive.

[Strider50]

Hi! I'm having a very similar problem with the same model of laptop. Where can I find PLT_RST and how did you fix it?

[johnbeton]

Hello,

In this link you can find the schematic and boardview:
https://www.badcaps.net/forum/troubl...c-s550-nm-c811

Look in the boardviewer for the net 'PLT_RST#' and you will easily find all components that are part of 'PLT_RST#'. You can then measure voltage and resistance to ground.

In my case I fixed the laptop with flashing the bios. This is 1.8v bios, and you have to desolder the chip from the board to flash it. Still on the board the circuit will interfere and flash will fail.
I first tried flashing with CH341A programmer with 1.8v adapter, but gave no error, I assumed flash was OK, but it wasn't. With the new programmer it worked flawless.