Guys, some hardware #HelpWanted (or rather, advice). My #motherboard burst into smoke 🔥 and now it's okay 😮
🧱 So, I had this problem where my laptop went completely unresponsive: no charging, no powering on, no indicator lights, nothing
🔌 Tried a new power adapter + opened up and line-tested the power socket but no response
🔥 Decided to connect up and try once more. Battery + other indicators finally came on...and also a mini explosion with smoke! So I quickly disconnected
🧵 1/3
👢 Came back after half an hour and (for no logical reason) tried again...and this time it booted up! (Only till BIOS, because no drives connected yet)
🔍 On inspecting the board, I see a burnt-up SMD called "C588", which I'm assuming is a capacitor
📖 No circuit diagram for my motherboard (#Thinkpad #X230T) but the diagram for a similar(ish) model (#X230, the non-tablet version) seems to say C588 is part of the voltage regulation circuit, in parallel with a couple of other capacitors
🧵 2/3
🤔 Either way, my theory is the capacitor was shorting, preventing anything else from powering. And when it finally burnt out, the other circuits started to work
❓ Question being, is that a valid hypothesis? Or should I check for other upstream problems?
🔩 Thinking of reconnecting and running sans that capacitor, atleast until I get a replacement cap. Internet tells me capacitors are for smoothing power and can be managed without (of course I'll seek a bit more expert advice first!)
🧵 3/3
@badrihippo I had a similar smoke issue like this too, not on the Thinkpad but my x86 tablet.
No power, no charging, no nothing.
Any smart charger would shut down once plugged in, but trying another charger (yes, I know, that's a dumb idea) seems to have burned out something & the tablet started to work again.
It's been a year now since the incident, everything still works except for the USB host part which was rarely used because there's two ports (one for charging and another for data-only).
@danct12 interesting! I didn't know (or wasn't fully aware) that smart/dumb charging was a thing. I did use two chargers so let me check what kind they were again 👀
Do you mean one USB port stopped working and the other one was fine?
There are two ports on my tablet (both are Type-C), one is used for USB host and that's it, the other one is for OTG, data transfer and charging.
After the incident, the OTG part of the port stopped working, but still charge and I can still transfer data to my computer using a data cable just fine.
@danct12 ah okay, that's good!
In my case it's working (in fact, I'm typing from that laptop now) but unfortunately the battery charging circuit is gone. It runs on battery, but if both power and battery are plugged in I hear a sizzling sound 🔥 so there's no way to charge it.
Anyway, using it on mains for now, and going to get a replacement motherboard in a bit. TBH I'm glad there *is* a problem; was a bit disconcerting to have a component blow and then everything work as normal! 😅
@badrihippo this link, as sus as it looks, does seem to have a valid comet-2 schematic
https://disk.yandex (dot) u/i/ZrV27zTLFKKWwg
Happy to email it if you'd prefer?
@nroach44 ooh smart! 👌
By the way, I looked it up and, though different from the other model, the capacitor is indeed used for power regulation 🔋
Specifically, for charging the battery, because my laptop is running on both power and battery independently, but when I plug in both I hear a sizzling from inside 😬
Posting this from that laptop plugged into the mains with no battery!
@badrihippo Nicely figured out!
Since that's a decoupling cap, if you carefully snip it off or desolder it, it might work fine.
@nroach44 I mean there was a bit that came off when I pulled but I didn't attempt to clean beyond that, so there might be something left Hmm, maybe that was the sizzling?
What's a decoupling cap and what does it do? Sorry I'm new to this 😅
@nroach44 okay, found these:
https://www.learningaboutelectronics.com/Articles/Decoupling-capacitor.php
Making more sense now 🙂 maybe I'll give it a try tomorrow!
@nroach44 well, looks like whatever remaining material there was disappeared overnight (or the last time I checked). Battery charging properly now!
I should probably open up once and clean that spot though 🧹️
Hippo 🍉
[danct12@fosstodon ~]$ 
NRoach44