carbon x1 not always connecting to thunderbolt dock 3

[meeotch]

I have an X1 5th Gen, and a Thunderbolt Dock 3 1st Gen. In the past few months, I've been getting an issue where when the dock is plugged in via the thunderbolt cable, I get only one "device connected bong" noise, I do get AC power, but none of the devices connected to the dock (USB keyboard & mouse, monitor, etc.) When this happens, the View Attached Devices window in the thunderbolt software shows nothing connected. When it successfully connects, I get several bong noises, all the devices work, and I can see the dock in the thunderbolt View Attached Devices window. I'd say that it fails about 50% of the time, and unplugging/replugging fixes it - but sometimes it takes several attempts.

I have tried multiple thunderbolt cables, including the original one that came with the dock. I have tried both USB-C ports on the X1. Neither seems to make a reliable difference. All software is up to date, according to Lenovo Vantage. I reinstalled the dock firmware (which was already on the most recent version). And in fact, after the issue started, I had the motherboard replaced under warranty, due to an unrelated broken USB port - which I assume also replaced the thunderbolt ports. Windows 10 is completely up-to-date.

Has anyone else noticed this behavior? If so, did you find a fix? It's not the end of the world, but since my warranty ends on Tuesday, I'd like to know if I should put in a service ticket while I still can. (But I don't want to risk another motherboard replacement, then have the warranty expire, if the problem is in fact software related.

[axur-delmeria]

I don't have an X1 Carbon (nor any Thinkpad with Thunderbolt ports ), but the your issue reminded me of this: https://support.lenovo.com/us/en/soluti ... s-thinkpad

[meeotch]

Thanks for the reply. I have seen that page, and confirmed that my system is up-to-date based on the chart. (I even re-installed the listed dock firmware.)

[RealBlackStuff]

Also check this: viewtopic.php?f=58&t=134730

[dr_st]

It's not the end of the world, but since my warranty ends on Tuesday, I'd like to know if I should put in a service ticket while I still can. (But I don't want to risk another motherboard replacement, then have the warranty expire, if the problem is in fact software related.

I had been told once, a long time ago, that whenever Lenovo replaces a part, the part receives a 90-day warranty, so if there is a defect in that part, they will replace it even if the original system warranty has expired. Perhaps the warranty is even on the repair job itself (so should cover anything else they may have broken in the process).

I never had to test this policy, and it may have changed, so I would bring that point to the service agent, if you do end up opening a ticket.