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**piernov** · 05-29-2022, 11:06 PM

Re: Thinkpad X1 Carbon gen2 (LMQ-1) no power

Haswell has FIVR, input voltage is 1.6-1.8V.

**Norrecito** · 05-30-2022, 12:39 AM

Re: Thinkpad X1 Carbon gen2 (LMQ-1) no power

Originally posted by nstrument View Post

Were you able to confirm whether all voltages come up correctly and what they're supposed to be? I'm also tinkering with a broken X1 Gen2 (power button flashes a few times, fan spins momentarily, nothing on screen) and I can't figure out what "VCCCPUCORE" is supposed to be. U16 should be generating it and when I measure the voltage on L1, I get ~1.75V for 500ms after pressing the power button and 0V after that. This seems odd to me since VCore for an i7-4600U CPU is 0.68V, not 1.75V.
The schematic is just calling it "VCCCPUCORE" without specifying the value anywhere. There appears to be no datasheet for the V1334S Volterra IC (U16) either.

I've verified that all voltages that should be present with the charger plugged in are there. If I measure a voltage rail which is only present with the laptop turned on, (after pressing the power button) I could see voltage for a fraction of a second with the multimeter but it goes back to zero just as in your case.

I had to give up on this motherboard for now because the problem is well above my current knowledge. (Managed to fix 3 other laptops in the meantime)

I would like to revisit it in the future so if you make any discovery about the issue you are having I would love to hear about it

**nstrument** · 05-30-2022, 06:18 AM

Re: Thinkpad X1 Carbon gen2 (LMQ-1) no power

Originally posted by piernov View Post

Haswell has FIVR, input voltage is 1.6-1.8V.

Interesting... I guess the VCCCPUCORE rail is likely intact then.

**MmkGari** · 04-02-2024, 06:35 AM

Originally posted by Norrecito View Post

Hello,

After dealing with old video game consoles I'm trying to get into laptop repair (only as a hobby) but maybe I should have taken a smaller step.

Anyway I would like to request some help with a X1 Carbon gen2 (LMQ-1 MB 12298-2 48.4LY05.021 motherboard) I've bought that has no power.

Fortunately in this (very cool) forum, I have managed to find both the schematics and boardview file for this motherboard a

Hello,

Can you please share the schematic and boardview to this board? There are some boardview/schematics titled with 12298-2 and such, but none of them seem to match the exact board number 48.4LY07.021. I was hoping if you could share it here again if you have the exact same model.