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10-07-2020

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X240/Ultradock dual monitor blinking

2020-10-07, 14:43 PM

Hi all!

 

I have an x240 with a 40a2 dock (ultra dock) and a 45W PSU.

When I connect the dock to a dual external monitor (one is hdmi and the other DVI) I get a persistent blink with a period of approx 1 second or so. During this blink Windows sees to somehow stop me from accessing the start button and I'm unable to right lcik on the desktop or use the computer all together. The bizarre part is that I tried to open task manager and that is shown correctly.

 

From what I see it should be a sw issue as the Windows 10 bar disappears and make the computer unusable. If I connect only one of the screens at the time they individually work correctly.

The HDMI connected screen resolution is a 2560, while the other one (on the DVI port) being smaller should be set at a lower resolution. Unfortunately I cannot realyl verify it as the computer is unusable until I remove on od the screens from the dock connector.

 

I have tried to set the intel HD graphics software to "maximum performance" but to no avail.

 

Has anyone has a similar issue and has managed to solve it?

Might this be a PSU issue? I should buy a more powerful PSU?

 

ps the dock firmware is up to date and so are the intel display drivers on the x240.

 

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5226 Posts

04-25-2008

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X240/Ultradock dual monitor blinking

2020-10-07, 15:11 PM
Per the Setup Guide, the minimum specified power supply for this dock is 90W. So your 45W PSU might be the issue.
USB-C: Just cos it fits don't mean it works.
I don't work for Lenovo. I'm a crazy volunteer!
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5 Posts

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Re:X240/Ultradock dual monitor blinking

2020-10-07, 15:14 PM

I thought it might be but what puzzeld me is that below the dock the current ratings are and it appears that 2.25, 3.xx,4.xx, 6.xx, 8.xx are all accepted(which times 20V gives the power). Are you referring to the guide of x240 or the Dock?Shoudl I just cut it short and buy another (more powerful) Psu?

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Re:X240/Ultradock dual monitor blinking

2020-10-07, 15:20 PM

Excerpt from the 40A2 Dock Setup Guide: 

 

"Use only an UL Listed Power Supply, rated 20 Vdc 4.5A (90W AC Adapter), 20 Vdc 6.75A (135W AC Adapter), 20 Vdc 8.5A (170W AC Adapter), or equivalent."

USB-C: Just cos it fits don't mean it works.
I don't work for Lenovo. I'm a crazy volunteer!
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Re:X240/Ultradock dual monitor blinking

2020-10-07, 15:41 PM
Thank you. I'll give this a try but I could not find the setup guide on line. I'll keep everyone posted to see if this works.
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Re:X240/Ultradock dual monitor blinking

2020-10-10, 15:04 PM

Hello, it appears that using the 90W psu has not changed the final result: the screen is blinking. 

 

I suspect it may be a driver issue: a few instants before blinking Windows appears to be loading something and then blinking starts.

 

Other than trying with another OS does anyone happe to know of similar issues solved via software/drivers?

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5 Posts

10-07-2020

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Re:X240/Ultradock dual monitor blinking

2020-10-10, 15:14 PM

OK!! For anybody wondering it was as fotware issue but not dictated from the driver!I use a software called start 10 and uninstalling it removed the issue.

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