On Thu, 26 Sept 2024 at 13:01, Pavel Machek <pavel@xxxxxx> wrote: > > When I press power button, it starts producing some noise (hdd > spinning up), but power light goes pulsating, not on, and I stare at > black screen. No beep? > I removed everything, let it sit for a while, but behaviour was the > same. I'm now letting machine "cool" with everything removed, > but... It seems EC is very confused. > > Should I try removing CMOS battery? It probably won't help. Last time I had something like that, it was the EFI variables being messed up and messing up the boot as a result. That's all in flash. The CMOS battery these days tends to really just be for maintaining the real-time clock. But if it's easy to get at, it won't hurt to try either. > Is there some magic combination I can hold during boot? I don't see anything about keys during power-on in https://download.lenovo.com/ibmdl/pub/pc/pccbbs/mobiles_pdf/0a60739_04.pdf but you can try the usual suspects (hold ESC / Fn / etc during power-on). But that lenovo pdf says 1. Make sure that every connector is connected tightly and correctly. 2. DIMM. 3. System board. for your symptoms. That said, my first suspicion would be a dead harddisk, just because they happen and you hear noise (but it migth just be the disk getting power on its own, and making noise even with a dead system board). The BIOS _might_ be trying to resume from sleep from a dead disk, and not even initializing anything else. And the disk is easy to get at, so try just removing it first. That might get a stuck BIOS unstuck, and you'd get a "no harddisk" error instead of a hung BIOS that tries to access something that doesn't reply. At least that way you'd have a suspect. Linus
