Screen going blank with USB-C on Thinkvision with T14, "Power Source Change"

[hyde]

Hi everyone, I just took delivery of the gorgeous T27HV-20 with a new T14 AMD 6650U.
At two different work sites, with same setup (USB-C to Monitor, no other devices other than 1 USB keyboard) I am losing power/connection between thinkpad and the monitor regularly. It's on a irregular interval.
We don't have any other USB-C monitors to test this, but 2 different monitors have same issue.

When I check the event viewer, the logs indicate there is "Power Source Change" which sometimes happen within few minutes, sometimes within few seconds. It's extremely distracting and frustrating not being able to pinpoint the cause.

[dr_st]

Flaky cable / Thunderbolt port on laptop?

I would also make sure that drivers and firmware are updated, where possible.

Thunderbolt/USB-C is really not a simple protocol. Lots of potential for glitches, especially when power and high-speed display data are involved.

[hyde]

Flaky cable / Thunderbolt port on laptop?

I would also make sure that drivers and firmware are updated, where possible.

Thunderbolt/USB-C is really not a simple protocol. Lots of potential for glitches, especially when power and high-speed display data are involved.

Thanks, It's really odd, I swapped to a 2nd laptop (T490) and then later back to my T14 and it hasn't happened ever since. Shouldn't it happen all the time? I opened a case with lenovo they suggested to run some hardware tests and bios updates and report back but I haven't tried yet since it has been working fine all day today.

If it was the port on the laptop, it shouldn't happen with the 2nd port, but it was happening with either USB-C port, this made me think it could be driver or BIOS issue.
Commercial Vantage System Update shows I installed the latest BIOS (1.35) on 5/23. Problem was still happening on 5/24. As of now, it shows system is up to date, shouldn't it be detecting the monitor's drivers are not up to date or installed?
When I checked Thinkpad website, lenovo does not mention any specific Windows 11 drivers for the monitor.
https://pcsupport.lenovo.com/us/en/prod ... 0Utilities

[hyde]

It happened again after not happening for more than a week, I am not sure what is causing it, might be faulty connection because it fixed itself after disconnect/reconnect.

[RealBlackStuff]

Is the LCD cable fixed on the monitor side?
If not, try another cable.

[hyde]

Is the LCD cable fixed on the monitor side?
If not, try another cable.

It's not fixed cable, it's the USB-C <-> USB-C that came with the T27HV-20 Thinkvision monitor.
I have 2 of these monitors, and had same sporadic black-out experience with 2 different monitors on 2 different cables, at 2 different locations (one home, one in office)

[hyde]

It's extremely annoying how it happens sometimes and not other times, and seems like there is no correlation between this and any other event.
Event Viewer just mentions "Power Source Change" but does not mention any other previous event or activity that triggers this. Is there a way I can find where "USB-C Inserted/removed" or when it is disconnected that results in power source change?
Am I the only one who hates the direction Lenovo is taking with discontinuing the physical docking ports either under or side mounted ones?

[hyde]

This was not happening for a while and it suddenly started again, and it happens on irregular intervals. At the office I thought it was my wireless charger drawing too much power from the monitor (that I just tried) but I am now at home with exact same setup (monitor + USB-C to T14) and nothing else plugged (except the USB SK-8855 to the monitor) and it's happening again.

This is driving me insane because I have to stop what I am doing and wait for the screen to come back, sometimes 1 second, sometimes few seconds, and when this happens the light on the lid on Thinkpad logo blinks, obviously it is switching power sources from monitor to laptop, but sometimes it does not blink. I see my battery is 97% even though it should have been 100 by now, is it possible some setting in the laptop about how it needs to drain the battery so it's not always overcharging? Is there way to turn this off completely?

Also why can't I change performance from BALANCED? It's the only option Lenovo is giving me.

[RealBlackStuff]

Saw this, maybe it helps: https://superuser.com/questions/1743151 ... o-ac-power

Lenovo website has this problem multiple times: https://forums.lenovo.com/t5/ThinkPad-X ... -p/5040633

Yes, I believe it is a power issue. I now plug in both my dock and a separate power adapter and have not had the problem since. A pain, but it works.

Time to start hating USB-C with a passion.

[hyde]

Saw this, maybe it helps: https://superuser.com/questions/1743151 ... o-ac-power

Lenovo website has this problem multiple times: https://forums.lenovo.com/t5/ThinkPad-X ... -p/5040633

Yes, I believe it is a power issue. I now plug in both my dock and a separate power adapter and have not had the problem since. A pain, but it works.

Time to start hating USB-C with a passion.

Thank you so much, especially for the 2nd link. I was able to poinpoint the issue to power source change, but it doesn't explain if there is an issue with the laptop or the monitor or if the laptop is way too sensitive to fluctuations in power, and if we should be using a different type of power supply. I will also consider plugging the monitor to an UPS, this way we can be sure the input is constant and without interruptions from the main line.

If that doesn't work, I will try to get a 3rd party USB-C hub, with dedicated power supply, this can also test because the monitor will be powered by itself, with additional power to the USB-C hub. It's messy but if it works it's one less thing to worry about.