Author Topic: Bootlooping Thinkpad X230i - No backlight - No image (schematics included)  (Read 224 times)

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Offline Romanizer

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Hello fellow Engineers and hobbyists,

A couple of days ago, I got a broken Thinkpad X230i from a friend, saying it was unfixable and he saved it from recycling.

Here is the problem:

When turning it on, it stays on for about 5 seconds and then turns off again. This repeats indefinitely and happened when battery and/or charger(20V Bench PSU) powered. While bootlooping, it shows no image on screen and the backlight is off, but The Keyboard light and the thinklight are both on.
I checked all rails: 20V DC-in, 5V, 3.3V. All are present. The only rail I could make out that is missing is the VCC_GFXCORE_I rail for the CPU's integrated GPU. I'm guessing its an i3-3310M.

The VCC_GFXCORE_I rail is provided by a VT1324SFCX, which in turn is controlled by a VT1318MFQX (schematics attached, see pages 79 & 80).

I tried injecting Voltage into the rail, to see if there were shorted caps, because my meter was measuring about 1.4 ohms. But no luck.
I noticed that the power management IC VT1318MFQX is sending a fault signal to the buck converter VT1324SFCX telling it to shutdown.

Does anyone have an idea to what is wrong with my newly acquired Thinkpad?

Any help is greatly appreciated!!
« Last Edit: June 07, 2019, 08:18:34 pm by Romanizer »

Offline Rasz

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lack of VCC_GFXCORE can be faulty bios, bad ram, etc, GPU is brought up late in boot process
but 1 ohm on gpu-vcore is too low, take off L29 and check which side is low resistance

or buy <$20 replacement motherboard
even $10 with fan controller defect

personally I LOVE x220/x230 motherboards for small projects(home routers,nas,camera servers etc), they cost less than raspberry pee while delivering x10 the performance and IO. I usually buy ones with defects like one USB port blown for $5-10 including lower case (means comes with radiator/fan and often wifi/bt)

Who logs in to gdm? Not I, said the duck.
My fireplace is on fire, but in all the wrong places.
The following users thanked this post: Shock, Romanizer

Offline Romanizer

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Thank you for your response!

I was guessing that the GPU might not come up after a couple of seconds after boot, but my scope was confirming that the VCC_GFXCORE was trying to turn on.

I can rule out bad ram, because I tested multiple sticks in various configurations. I'll take of L29 and try locating the short then. :-+

I'll order a 'new' mainboard as a last resort, first I will see if i can fix it very cheap. If not the mainboard are super cheap aswell, i did not expect that. :D

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