ThinkPad X1 Carbon 2. Gen 20A7: 5 beeps at start up

[Dobbi225]

Hallo everyone,
first post on a new account. Sorry, if this problem was already addressed, would be thankful for a link, Search turned up empty though.

I have got a 2. Gen X1 Carbon which I did not use for 3 months and it refuses to boot.
On pressing the power button the keyboard lights up for a few seconds but other than that nothing but two times 4 bios beeps which hints to a power problem.
Being a six year old machine that was without power for longer periods of time, I changed the CMOS battery already, hoping for a cheap fix.

Now I get two times 5 bios beeps on startup, still nothing else. According to Lenovo’s website this hints to a CPU issue. I suspect the Mainboard might be faulty.
Is this a known thing and do you experts think changing the Mainboard for a used one if I can source one with the right specs will probably solve it?
The Laptop is in every good condition otherwise and I would hate having to dump it for some cheap replacement but buying a used Mainboard at around 160€ with no way of knowing if that will fix my problem is no easy call either.
Thanks for any input you might have and sorry for the wall of text.

Best, Dobbi225

[w0qj]

Wow, you may wish to bring it to ThinkPad/Lenovo depot for repairs (or one of its authorised partners).