USB-C Display Issues w/ 7th Gen X1 Carbon

Connected my work laptop to the monitor via USB-C. It’s an older 7th gen x1 carbon that has two USB-C ports and supports DP + charging. Issues I’m observing:

1 - On cold boot, the Spectrum won’t turn on. Have to power cycle the laptop as the internal screen doesn’t turn on either. On 2nd boot, Spectrum will get the signal and display it.
2 - Intermittently, the Spectrum will lose signal and go blank for about 10 seconds.

I’m using a new 3ft ‘XAOSUN’ USB 4 USB-C cable that supports TB 4/3, USB 3.2, 100W PD 3.0. I am a little leery about random amazon brands, so I may experiment and get a more mainstream brand cable (ex. Anker).

Beyond that, I’m on FW 105 and have updated the thinkpad’s BIOS and thunderbolt firmware; it’s running Windows 10. I suspect that using a DP → HDMI cable would likely cut down on the issues, but I was hoping the one cable solution (charge + display) would suffice. Otherwise, no issues w/ the monitor (outside of the existing mode switch lag issue) w/ my gaming PC or PS5.

Just trying to understand if this is a Spectrum issue or a laptop issue, so would appreciate any thoughts.

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Hi @PrazVT,

I am quite skeptical with the cable as well.
Although there is one thing that you might want to try from the Spectrum side.

You can try toggling the USB-C Bandwidth setting which can be found on the OSD (under Input/Output). See if that helps.

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Hi @Cas - yeah I will likely get another cable and try that out as well. So right now, the USB-C setting is set at ‘high refresh rate’. When you say toggle, do you mean toggle it to ‘High Data Speed’ and back? I’ve just done that. Will see if that improves anything. Otherwise, it looks like booting the laptop with the monitor off and then turning on the monitor after windows login seems to get around the no display on boot issue.

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HI @PrazVT,

What I meant is to see if turning it to alternative settings helps. Since you had it on “high refresh rate,” you can try changing it to “high data speed”.

You didn’t mention it before, so I will also suggest you update your video driver since it helps in some cases.

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Sure understood. I’ll test it out in the other mode (ie monitor detection on cold boot). It does reduce the refresh rate to 30Hz, though. Will update on detection behavior.

Also, I did update the Intel UHD drivers so that didn’t seem to make a difference. There are options in the BIOS to select internal or external displays on boot. But I’ve avoided messing with those to avoid the possibility of the internal display not turning on, somehow.

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Also I see there is a new firmware - will try that as well.

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Alright, yesterday I updated the USB and scaler firmwares. There was an issue this morning when I switched inputs from my PS5 to the work laptop where the monitor would just not come on. It would keep defaulting to HDMI 2 (PS5). Eventually, I was able actually access the OSD menu. I corrected the USB hub to the type B, then selected USB C as the input. Mini came on. I just did a reboot a few minutes ago and the monitor came on immediately, so that is promising. Will try a cold boot later to verify.

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Okay at this point, the major issue is that the monitor doesn’t get a USB C signal if I’ve previously swapped inputs to play PS5 and then turned off the monitor for the night. The laptop remains on through the night. Next morning, I turn the monitor on and set the input to USB C and nada. No signal, defaults back to HDMI 2 (PS5, which is in rest mode). Have to reboot laptop to get monitor signal again. Thoughts?

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Hi @PrazVT,

It looks to me like there is some setting within the laptop itself that refuses to transmit video signal because it did not detect Spectrum when you switched inputs.

Try changing the multiple displays setting on windows to “duplicate” and see if it works.

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Yeah it might be the laptop - I’ll just deal with it for now. However, I seem to now be having an issue with my desktop and HDMI 1. I was trying to update the motherboard BIOS and when it reboots to flash mode, the Spectrum will briefly flash grey for a split second and then just sit there saying no signal. It wouldn’t even turn on when booting into Windows. Finally, I had to connect a DP cable to get the monitor to detect. It’s an MSI x570 MEG ACE / 5800x and an eVGA 3080. Connecting the HDMI back and disconnecting the DP in Windows works. But I’m having to use DP for this BIOS activity. This is really making me nervous. Monitor was fine up until I maybe updated to 105 or 106. Also sometimes, the input labels will show in yellow.

Anyway sorry for sidetracking to another issue but just trying to establish if it’s a monitor hardware or firmware issue.

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Hi @PrazVT,

Have you tried unplugging and connecting back in the HDMI cable after getting no signal when updating the BIOS?

I’m not sure if this is a monitor or firmware issue at this point. The yellow input label is a a bit odd. I’ll have to look into it further to see if I can find out anything for you

Does the OSD show in yellow as well?

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#1 - Laptop: I replaced the random branded thunderbolt 4 cable with a Belkin thunderbolt 3 cable last night. Work up this morning and turned on the monitor (laptop was on already) and it’s still connected. I think the HDMI out on the laptop is dead though, as a new HDMI → DP cable did nothing (uni-directional cable). Will continue to test this, but so far so good.

#2 - Desktop: So in the MSI BIOS, when you want to flash it, the computer will reboot into the BIOS flashing UI. This is the step where the monitor wouldn’t turn on - there’d be a partial light grey flicker near the bottom of the screen and then a ‘No Signal’ message. I did unplug the cable and reconnect it with no luck. I had another brand new HDMI 2.1 cable (same moddel) which I connected as well with no luck. I powered down the desktop and unplugged the monitor for about 10 minutes and tried again, with the same results.

Eventually, I grabbed a DP cable and the monitor managed to maintain signal when rebooting into the BIOS flash screen. After the BIOS flash, I booted into Windows 11 and swapped back to HDMI. Monitor detected the signal. I ran a windows update and rebooted the desktop and HDMI was working again. Throughout the evening, swapped among USB-C (laptop), HDMI 2 (PS5) and HDMI 1 (Desktop).

Regarding the yellow OSD signal message, it’s just the verbiage that shows the different inputs you’re cycling through. When a source is recognized and the actual full OSD Menu is available, that menu is fine. And the yellow input name occurrence is intermittent.

The only other thing I noticed is that sometimes the default USB hub will change from type B to type C. However, I have power cycled (unplugged) the monitor a few times. So maybe that resets that option?

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Just booted the desktop and switched inputs. No signal. Here is a quick video of what I’m seeing. CTRL-Alt-Del, one more flash, and then the picture came back on.

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Thanks for the video, that will help immensely when Theo and I have our next meeting with the fw dev team.

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