Lenovo Ideapad 5 15ARE05 random freeze

[EsIstSimon]

Hi there,

i have a Lenovo Ideapad 5 15ARE05 that will freeze randomly.
Sometimes it wont even post, sometimes i can use it for a couple seconds or minutes before it completely freezes.
Sometimes the screen freezes, but still displays the last frame, sometimes (pretty rare) the screen goes black

It does not matter what i do. Installing windows, starting Fedora or just sitting in the bios. After some time it will freeze.
When the freeze occurs, the laptop draws a pretty constant wattage (it will just stay on the value that it draws, when it locks up +- couple hundred mw) and will never return to a functional state.
It does not seem to matter if its a cold boot or if it power cycled a few times.
When it posts (screen comes on and Lenovo Logo appears) and i shut it down right away, it works for the next boots without an issue.
When it has frozen once, it takes some time and/or trys to get it back to a working state.

In this no post state, starting the laptop will turn on the keyboard backlight and fan for 2-3 seconds, both then turn off and the laptop draws ~14watts.
I can still turn on/off the keyboard backlight, but Capslock / Fn lock wont work. The cpu will heat up and the fan will come on from time to time.

What i have tried so far:
- Remove battery and CMOS and perform a static discharge
- Remove everything connected to the board
- Reflash Bios. I extracted it from Lenovo updater and trimmed the file according to the original backed up bios. I flashed it with a CH341A, while the BIOS chip was still on the board. I read in one or two threads that people recommend flashing the bios out of circuit, do you think i should give this a try?
Also i have not transfered the DMI to the new BIOS yet, as i wanted to test it first, but this should not be the problem here, right?

The board is completely clean and since it will work from time to time, i dont think anything has blown.
My best guess would be a failing APU, but since i am pretty new to the world of electronics repair, i kind of lack the experience to be sure about that.
I was thinking about a mild reflow of the cpu, but i am not sure it this will result in anything, since it does not matter if the cpu is cold or not.
Another guess would be a failing memory chip.

Maybe you guys have another idea and can nudge me in the right direction

Thanks a lot!

[EsIstSimon]

Re: Lenovo Ideapad 5 15ARE05 random freeze

Since i got no response here, i just went for my best guess and did a reflow of the cpu.
Machine works like a charm (at least for now) =)

Maybe this information will help someone in the future.

Cheers

[mcplslg123]

Re: Lenovo Ideapad 5 15ARE05 random freeze

Reflow of the SOC wont work beyond a couple of days. You need to reball it.

[Corentinrhr]

Hello, I have exactly the same problem with the same laptop model. Does the reflow of your CPU still work to this day? How did you do it?

[javieromex]

I have same issue with same model. Board: NM-C811. Do you know how to remove the black epoxy? Otherwise I will try with reflow

[mcplslg123]

Dont even attempt a reflow without you being able to remove the black glue. Else situation will worsen further. Simplle physics-on heat,element will expand and the glue wont allow it to expand-so will result in damage to SOC.

Removing that glue is a nightmare.Often the PCB pads gets damaged.

[ictc]

I'ma having the same issue with an IdeaPad ryzen 5, I thought could have been the onboard ram failing but that should not explain why after crash the CPU temperature suddenly rise up of about 5 degrees. I also tried replacing the bios with no luck at all. I'll try the reflow and if anything changes in better I'll manage to perform a complete reballing. Do you have experienced other random freeze after reflow?

[mcplslg123]

Lenovo use low temp melting solder and its not that easy to succesfully desolder the cpu 'coz of black glue as u cant go with very high temp.

I still struggle with SOC reball on lenovo.. Btw, i hate BGA work anyway.

[ictc]

I managed to desolder the CPU with only a couple of not connected pads ripped off. I found out that the very thin PCB thickness allow an easy and fast desolder compared to other thicker motherboard. The dark glue was not actually a problem. My only problem now is finding the right stencil to reball the CPU. I also caused some solder mask to peel off during desoldering and I need to reapply the green oll entirely without a proper stencil...that would be the most annoying part so far.