As the title states I've recently started experiencing various tears, glitches and signal losses on my external displays when trying to work on my work laptop (Lenovo ThinkPad L380 Yoga, video here). The issues got bad enough to render external monitor work impossible.

The things I have tried to narrow down / eliminate the problem:

  • two different external monitors
  • tried different HDMI cables, conected both to:
    • laptop's own HDMI port
    • HDMI port of a USB-C dock
  • a VGA connector (through dock)
  • different OS (Windows 10, and Ubuntu 18.04)
  • double checked the graphics drivers, chipset drivers and BIOS are updated to their latest versions as per Lenovo's website
  • attempted to do a clean Windows install
  • set various refresh rates and modes for the external displays

None of those measures managed to eliminate the problem. I suspect the issue lies somewhere in the chipset itself, or the video card hardware. Unfortunately the laptop is out of warranty, and currently we have no replacemetns available at work so I would like to elliminate all alternatives before we send it out to repair. Hence the question:

How likely is it to be a hardware fault? If not, what other possible causes of the problems are there and what can I try to remedy them?

  • We have a couple of these at work too... We haven't seen this one before, but the keyboards keep breaking on ours. Not Lenovo's finest product. – Tonny Dec 3 at 20:01

You were really thorough with your troubleshooting, especially trying multiple OSes. If I was your IT department I wouldn't ask you do more with this equipment.

You can try this for more confirmation: Power off laptop. Connect your external monitor, then power on laptop. Then go to the BIOS or UEFI setup screen (before you boot into Windows). If the glitching happens there, it's definitely a hardware issue.

Laptop may be running too hot, so try dusting it out to see if that helps.

  • Tried that and the glitching doesn't happen. Although the only way I'm able to have external monitor work in this setup is by setting it up to be the only display used, so maybe the faulty secondary display circuitry is not used then? – KubaFYI Dec 4 at 13:04

Have you tried lowering the screen resolution and/or refresh rate? As a machines ages, cooling of the GPU (integral or separate) can be impaired by dust, and it might not be able to keep up with high demands.

If the display works at lower frequencies, then try cleaning ventilation holes, fans and heat-sinks with air. Though I've seen advice to replace heat-sink compound, it is not likely to help much.

  • Yes, I've tried lowering the refresh rates. I forgot to add it to the lit of things I tried. Will edit the question! – KubaFYI Dec 4 at 10:40

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