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darkbunny
Paper Tape
Posts: 3
Registered: ‎05-05-2018
Location: FR
Views: 1,740
Message 1 of 4

T470s (20HF) - Can't see Thunderbolt controller in Windows 10 (and can't use ext. display usb-c)

Hi Everybody,

 

Hope i'll find help here. 

I spent hours to make my T470s (20HF) working with external display (LG 27UD88-W) via USB-C.

 

I bought 40Gbps Belkin cable at price of gold.

I updated all my drivers (lastest intel 620, all stuff i've found on Lenovo, Installed the thunderbolt software/drivers from Lenovo 17.3.74.400
, BIOS etc).

Well it looks like every thing is up to date.

 

But I still don't have the ThunderBolt controller displayed in windows devides manager...

 

And of course my 4K display is not working.

When plugin USB-C C cable, the ext monitor detect something is hapenning, and Thinkpad is trying to use external display, but he doesn't success. The laptop screen blinks, CPU running high, something loops.

 

Well what's going wrong here ?

2018-05-05 10_35_54-Device Manager.png

Thanks for your help

 

Community SuperMod
Community SuperMod
Posts: 4,527
Registered: ‎04-25-2008
Location: US
Views: 1,716
Message 2 of 4

Re: T470s (20HF) - Can't see Thunderbolt controller in Windows 10 (and can't use ext. display usb-c)

Hi darkbunny, and welcome to the Lenovo User Community!

 

That's not a Thunderbolt monitor, so you shouldn't expect to see a Thunderbolt device. It does have a USB-C input. Do you have the LG drivers installed?

I don't work for Lenovo. I'm a crazy volunteer!
darkbunny
Paper Tape
Posts: 3
Registered: ‎05-05-2018
Location: FR
Views: 1,699
Message 3 of 4

Re: T470s (20HF) - Can't see Thunderbolt controller in Windows 10 (and can't use ext. display usb-c)

Hi Thanks for answering

 

Sure it's not a TB3 monitor, it's a DP1.2, but I thought, DP1.2 was "encapsulated" on top of TB protocol. Anyway.

 

Yes I installed LG drivers on WIN10, also, LG monitor is at latest availble FW release.

 

What is the recommandation for the cable ? This one is 2 meters longs, but certified TB3/40Gbps (BELKIN).

 

Any thought ?

darkbunny
Paper Tape
Posts: 3
Registered: ‎05-05-2018
Location: FR
Views: 1,668
Message 4 of 4

Re: T470s (20HF) - Can't see Thunderbolt controller in Windows 10 (and can't use ext. display usb-c)

Well, you know what ? This Belkin 40Gps (and expensive)  cable doesn't support alternate mode ! That was the reason with my screen wasn't displaying anything.

 

Tried 10Gpbs USB-C 3.1 cable : OK 4K60Hz

Tried 20Gbps TB3 : OK 4K60Hz

 

Both cables from Belkin.

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