Thinkpads Forum

This is a big one, but I hope it can serve folks to fix these awesome units instead of binning them or paying out the nose for a mainboard replacement.

For future reference, primary cause of this issue is the Thunderbolt (USB-C) port(s)' power mosfets degrading and burning out. The chip is a Texas Instruments CSD87501L. On the X1 Carbon Gen9 there's 2 of them, one for each of the USB-C charging supported ports).

These absolutely tiny fragile little buggers run a helluva lot of power through them for their size, and there's pretty much zero heatsink or airflow cooling on or near them. And it seems Lenovo went a little bit overboard with weight reduction so there's not adequate copper there for the chip to effectively sink its heat into the board through its solder joints and traces. I do believe there was a firmware update including some tweaks to improve heat buildup, but results have been marginal at best because code can't fix the underlying issue. Nor does the firmware help an already degrading or failed chip.

A whole bunch of other Lenovo models have the same issue, with the same chip, predominantly for the same reason (lack of cooling).

Depending on severity, failure mode, or if instead caused by a dodgy charger or a short in damaged USB-C charger plug or socket, I have seen cases where the USB-C PD charging controller chip has given up too, but this is much less common. That chip is a Texas Instruments TPS65994AD.

If looking to repair this, first: Inspect the state of your USB-C ports. Both inside the sockets and ideally their solder joints. If the port, pins or joints are damaged, the port(s) must obviously be fixed/replaced too or you risk having to replace the chip(s) all over again right away.

These are inexpensive parts so get them from a well known vendor to make sure they're not recyled (reusing components from donor boards can often be fine, but not in this particular type of case). I've mostly bought them from Digi-Key, there the power mosfet is about $1 USD and the USB-C PD controller is roughly $6 USD, when buying single digit cut-reel volume.

Different model platforms hsve different designs, so this part only regards to the X1 Carbon Gen9:

Replacing these chips is not soldering iron type work, these are extremely small BGA chips. Equipment for and perience with hot air rework / microsoldering is required. Be warned, these mosfet chips are of the PicoStar type package. They're extremely thin so quite fragile; buy a couple extra, they're really easy to chip and overcook.

The USB-C mosfets on the Gen9 are placed closely behind the ports and on the top side of the mainboard when viewed from the bottom while still inside the chassis. If you're good at it, shield the surrounding area from the heat, and got a bit of balls, it's doable to replace them with the board still in the chassis. However the Thunderbolt/USB-C ports are soldered to the other side, so if you need to check the joints or replace those, the board has to come out (same if working on the controller chip).

Many have issues with these getting even hotter even faster after replacing them. Primary cause of this is solder and overcooking. They have practically no thermal mass what so ever, and with effectively no cooling, you mostly rely on the chip to sink heat into the board via its joints and traces. These are power components so there are heat sinking power snd ground planes to deal with (just not enough for effective cooling); chunky enough to require preheating the area a bit. With the chip having so little thermal mass, I advice keeping the chip out of the way of the heater until the board is hot enough to solder. Don't go overboard with the flux if the board is still in the chassis.

You need to be really conservative on the amount of solder you use, so the chip doesn't ride high on tall balls but can be squished really really close to the board, with full pad coverage joints but without balls shorting. Also, because the X1 Carbon Gen9 has a metal bottom, once you've tested it, I advice removing the little plsstic flap that covers over the mosfets, and throw a dab of thermal putty on the mosfets so when you close it back up the putty contacts the metal bottom lid.

As to the controller chip. That's underfilled. I'm not gonna advice anything there. If you already know how to deal with underfilled chips, you don't need my advice. If you don't, I advice leaving that to someone who does.

My company bought over 10k Gen 9 X1 Carbons this year--lenovo repeatedly has refused to admit they were defective. The charge port on all of them have been failing 1 by 1. Just heard Lenovo finally capitulated, agreed to buy back all of them and replace them with Gen 10's. FYI--I suspect your mileage will vary in seeking accommodation from them.

How did you go about getting the replacement?

Our organization has had a failure rate of greater than 10% of Lenovo X1 Carbon Gen 9's, with the charging-failure-problem. I've been told over the telephone by the first-level-technical-support-people that they will not entertain replacing with a Gen 10 unless the same failure happens 3 times.

I'll see if I can get more details from IT--but basically i think it came down to my company of 20k employees, that is an all ThinkPad shop, threatening to permanently pull our business away from Lenovo because they refused to admit there was anything systemically wrong.

mikemex wrote: ↑

Sat Dec 30, 2023 11:14 am

I just got a super deal on an X1C9. I wasn't really looking to upgrade since I'm quite happy with my X1C5, but I couldn't pass on it. I have the perpetual issue to be a Spanish speaker and I find particularily hard to swap keyboard languages on the X1 Carbon series. This machine was far from top of the line (1145G7, 16GB, FHD) but was very well equipped otherwise (IR Camera, WWAN, slim 65W adapter, it even had the etherner adapter). The WWAN and Spanish keyboard combo was simply too hard to resist, since Lenovo doesn't offer WWAN option here in Mexico at any price. It was brand new in box, with warranty, for about $400.

RealBlackStuff wrote: ↑

Thu Jun 13, 2024 4:21 am

The standard 20V charger-cables with barrel or yellow-slim-tip plugs have only 3 wires (+/-/resistor).
I'd love to see instructions for where to solder these 3 wires into the USB-C/Thunderbolt circuit.
And then: bye, bye crappy useless USB-C!

RealBlackStuff wrote: ↑

Sat Jun 22, 2024 1:47 am

Thanks for that info, Mike.
My daily driver is still my trusty T440p with W7 (and no updates since 2018).
My 'newest' (reserve) laptop is a T480, which does not (yet) have any problems, touch wood.
Bought it in January 2023 but have only used it maybe 3 or 4 times.
But should I ever need another laptop, it won't be one from Lenovo.
They seem to get worse every year.

Crodo wrote: ↑

Wed Mar 05, 2025 4:21 am

Hi,

I'm new. So hello forum.
I just got X1 gen 9 with damaged upper thunderbolt. I bought it, because I got an amazing deal - I paid just $300 for the laptop in pristine condition, basically brand new, with brand new battery.

Crodo wrote: ↑

Wed Mar 05, 2025 4:21 am

My question is: is the second thunderbolt port also destined to fail, or these ports somehow differ? I read around the internet about this issue, and usually people mention about upper port going bad.

Crodo wrote: ↑

Wed Mar 05, 2025 4:21 am

Second question: are there any preventing measures to take care of the second, still working properly usb-c?

From what I understand, it has to do with components getting too hot. I assume it is a good idea then, to charge the laptop when its idling, or during light use, like web browsing, or documents work and avoid charging it while its heavily loaded, to prevent heat build up.

Crodo wrote: ↑

Wed Mar 05, 2025 4:21 am

Also I was wondering if it would be good idea to use 45 watt charger insetad of 65 watt, in order to reduce the heat during charging.

MasterYoga wrote: ↑

Sun Feb 08, 2026 2:34 pm

Is X1Y6 also affected by this issue? Has it been fixed in the X1C10 or the X1Y7?

babblefish wrote: ↑

Sat Feb 07, 2026 8:34 am

Glad I ran across this post. I just bought a X1 Tablet Gen 3 off eBay and while it looks brand new (not a scratch on it and perfectly clean, plus the installed Windows 11 has never been initiated), the CMOS battery was dead and the main battery won't take a charge from either port. I have a new main battery coming in the mail, but if that doesn't solve the charging problem, I'll have to look into replacing those darn tiny CSD87501L chips. The spec sheet says they're 3.37mm x 1.47mm x 0.2mm(!). I have a hot air gun, but I'm also 72 years old so my eyesight ain't what it used to be. On the other hand, I just replaced a SMD zener diode in an old Onkyo AV receiver that was 1.95mm x 1.35mm x 0.90mm using a soldering iron with a 1mm diameter tip.

Orions327 wrote: ↑

Mon Feb 09, 2026 9:52 pm

babblefish wrote: ↑

Sat Feb 07, 2026 8:34 am

Glad I ran across this post. I just bought a X1 Tablet Gen 3 off eBay and while it looks brand new (not a scratch on it and perfectly clean, plus the installed Windows 11 has never been initiated), the CMOS battery was dead and the main battery won't take a charge from either port. I have a new main battery coming in the mail, but if that doesn't solve the charging problem, I'll have to look into replacing those darn tiny CSD87501L chips. The spec sheet says they're 3.37mm x 1.47mm x 0.2mm(!). I have a hot air gun, but I'm also 72 years old so my eyesight ain't what it used to be. On the other hand, I just replaced a SMD zener diode in an old Onkyo AV receiver that was 1.95mm x 1.35mm x 0.90mm using a soldering iron with a 1mm diameter tip.

Finally, I sure all my 87501 are dead.
For testing, you can try short-cut both of them (CSD87501), don't worry, Laptop will be OK if it is OK before. Login to Bios and test battery.
I mean, We have to know exactly what problem.
I want to post some picture here but don't know how to do.