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ThinkPad Yoga 12 (S1, 20CD) kills itself soon after power up

Posted: Sun Dec 16, 2018 3:25 am
by marioman23
I'm just gonna copy my post from Lenovo's forum because ehh I'm tired.
Short story, found this Yoga on ebay cheap (as in under $20 cheap) with a cracked display and some body damage but it does boot to bios. Apprears to be fully functional except for it dying completely within a minute or two, less if it's warm. This has been happening before and after cleaning it up and replacing the thermal compound. Was gonna swap the SSD I've been using in my T400 into it but, for now not worth trying until I can get this thing to be stable. It cuts power hard, much like a thermal shutdown event. Fan will spin up for about 3-5 seconds after powering on and then nothing after, at least from what I've seen so far. I'd rather not give up on it so easily, seems like a machine with some real potential. Probably worth noting some of the chassis is broken off around the heatsink, as if there was a decent impact in that area before. Hinges are solid, keyboard, trackpad, etc are perfect.
Thanks for any help

(if anyone's curious I did type this on my T400, not gonna lie it's the most dead reliable thing I've owned... and I own a lot of retro and somewhat modern hardware, kind of a hobby?)

Re: ThinkPad Yoga 12 (S1, 20CD) kills itself soon after power up

Posted: Sun Dec 16, 2018 5:32 am
by dr_st
Welcome to the forum. :D

Do you have a chance to boot an OS and run some temperature measurement program, before it turns off, to confirm or disprove the assumption that the shutdown is due to overheating?

Re: ThinkPad Yoga 12 (S1, 20CD) kills itself soon after power up

Posted: Sun Dec 16, 2018 8:49 am
by RealBlackStuff
I'd say that machine took a dive, which also cracked something in the motherboard near the CPU.
AFAIK it has soldered CPU and RAM.
I think that as soon as it heats up in one of the above areas, it disconnects something, which kills it.
Try putting extra pressure on the CPU, maybe that gets it to boot?
Be glad you didn't spend more.
Round-bin: here we come! :(

Re: ThinkPad Yoga 12 (S1, 20CD) kills itself soon after power up

Posted: Sun Dec 16, 2018 2:46 pm
by marioman23
Nope, definitely dies too fast to boot anything. I did notice the caps on the backside of the board under the CPU get quite hot fast, which is somewhat concerning. Ahh well I'll keep messing with it, but it does have some good parts if I can't revive it...

Re: ThinkPad Yoga 12 (S1, 20CD) kills itself soon after power up

Posted: Mon Dec 17, 2018 12:27 am
by marioman23
I think I might have found something.. a few things but. Should mention there were a lit of screws missing. Only two motherboard screws and three screws on the back panel were present. 2.5" Torx 6 head hard drive screws worked well. I noticed a couple of spots with traces of liquid (one on top of the SD card housing) seemed more like an oil or something, not a water base. The big thing was I noticed an Inductor right above the CPU that looked a little off. Solder looked funny, and the plastic sheet it was touching was melted. Actually it was stuck to the inductor. I have a feeling that's getting hot and causing the shutdown.
Now to figure out if I can manage to replace that thing...