x1 Carbon Gen 9 HYG60\HX4B0 NM-D341 Rev: 1.0, CSD87501L Failed solder Joints.

[abajor]

I had a x1 Carbon Gen 9 come in with a no charge and no USB C power up problem (the machine would turn on with a new battery until it lost charge).
I noticed lifting the protective black membrane near the USB jacks that two little BGA chips were stuck to the adhesive and had fully released from the mother board, one of them looking fully scorched. Q261 and Q263 power MOSFETS.

I found the schematic and diagram for the board here.
https://www.badcaps.net/forum/troubl...d341-schematic

I'm keeping my fingers crossed that this is the only issue. I don't think I've ever seen BGA chips desolder themselves like this before.

[mon2]

These are LGA packaged components and have very little meat with respect to the solder balls to keep them in place. You can try to flux and rework the parts back into place.

Alternatively, you can purchase new ones but keep in mind that the chip is supplied without solder balls (castrated) so you will have to reball these using an appropriate SMD stencil.

CSD87501L 30-V Dual Common Drain N-Channel NexFET Power MOSFET datasheet (Rev. B) (ti.com)

CSD87501L Texas Instruments | Discrete Semiconductor Products | DigiKey Marketplace

[abajor]

These are LGA packaged components and have very little meat with respect to the solder balls to keep them in place. You can try to flux and rework the parts back into place.

Alternatively, you can purchase new ones but keep in mind that the chip is supplied without solder balls (castrated) so you will have to reball these using an appropriate SMD stencil.

CSD87501L 30-V Dual Common Drain N-Channel NexFET Power MOSFET datasheet (Rev. B) (ti.com)

CSD87501L Texas Instruments | Discrete Semiconductor Products | DigiKey Marketplace

You don't think I can get away with packing a bunch of solder paste on the pads and yolo-ing with a hot air tool balling them onto the surface of the LGA?

[abajor]

It worked pretty well to just cover the CSD87501L with solder paste and use low velocity hot air. I would often get a bridge between a couple of the pads, but it was easy enough to remove with an Iron.

I got this laptop sort of back up and running. One of the USB-C ports will trickle charge the laptop at 5V drawing a max current of 2.22A, In some conditions it will ask for 20V and charge better.
I'm not sure if that's an issue with the data communication lines? This jack will not connect to USB drives.

The Rear USB-C Jack will not charge, but works for USB drives. Very Odd behavior. I will check some of the ESD diodes on the com lines.
I suspect this board had a solder flow issue during manufacture because I found an important inductor L79 loose, and the power mosfets in question were stuck to the black insulation plastic when I removed it.

[mon2]

Nice!! Good feedback. There is another thread on this forum that appears to have a fault on the same looking dual mosfets.

[abajor]

Nice!! Good feedback. There is another thread on this forum that appears to have a fault on the same looking dual mosfets.

The plot thickens. I wasn't happy with it's weird behavior there were some chips I couldn't see because the heat sink was hovering over them, and this is what I saw after removing heat sink.

The weird part is there is absolutely no corrosion I've noticed anywhere else on the board yet this happens to be well away from any ingress points.

[abajor]

I'm still hacking away at this board. I was wondering if anybody has any info on the intel JHL8040R BurnsideBridge re-timers. I'm trying to figure out right now why this machine doesn't want to request 20V from the USB-C.
While it does charge at 5V slowly, the battery will just drain at heavy loads while plugged in. I'm currently poking around the silkscreen and the schematic to see if I can puzzle out more info on this board.

[abajor]

Looks like the chip in questing is the TPS65988 AD For USB-C Power Delivery

[abajor]

At least one of the NSR20F30NXT5G Schottky Diodes are shorted TBTC_VBUS20 coming from the TPS65988 chip. Hard to tell if the chip is fine until I get the replacements.

[abajor]

correction it's a TPS65994 USB-C Power delivery chip

[abajor]

Funny I came across another of these x1 carbons. Allegedly a Lenovo tech came and replaced her board while it was under warranty; however, one of the jacks still wasn't working and the tech said oh its just a loose jack you can only use one.
That sounds pretty sleazy since the jack comes along affixed to the replacement board.

I just received it because the charging has gotten erratic.

When I opened up the laptop I saw the attached images.

These are the same components I had an issue with, so it must be a very common failure mode for this model. There was also a bit of semi melted solder paste stuck to the board so whoever did the work didn't bother to clean up much.

I'm hesitant at this point to take this laptop any further, I was only able to get the other one to charge intermittently.

[chrissan]

Hey! were you able to find and fix the problem?

[abajor]

Hey! were you able to find and fix the problem?

Unfortunately no.

Wasn't able to identify where the other issue was coming from.