One workstation has had intermittent monitor blackouts for more than a month. The displays lose video signal and sometimes produce brief static or visual noise first. Either one or both monitors may go dark, usually one followed by the other, and the interruptions happen often enough to seriously disrupt the user.
The problem seems tied to this particular user or workstation rather than one specific computer: it has occurred with multiple laptops, while the same docked computer works normally elsewhere. Replacements so far include the Lenovo ThinkPad T14s laptop, Lenovo Universal USB-C dock (40AY), Dell E2424HS monitors, power cables, DisplayPort cables, the dock power supply, keyboard, and mouse. The network cable was removed and the workstation was tested over Wi-Fi. Power was also temporarily supplied from another location, with no improvement.
What else could cause this kind of intermittent display failure, and what should be tested next?
4 Answers
Update the entire graphics chain, not just the laptop driver: BIOS and chipset drivers, Intel or AMD graphics drivers, USB-C and Thunderbolt components if applicable, and the dock's firmware. Also check whether Windows is repeatedly logging display-driver resets or USB-C/DisplayPort link errors. A clean graphics-driver installation can help rule out a corrupted software stack.
Do not overlook environmental triggers. Nearby two-way radios, industrial equipment, unusual electrical devices, or even a magnetic webcam cover or jewelry can cause a laptop to briefly enter or exit sleep on some models. Watch whether the blackout lines up with a nearby radio transmission, chair movement, or the user's hands near the laptop. Testing the user at another desk with the same peripherals, or moving this setup to a different area, may separate an environmental issue from a profile or dock problem.
Since the issue follows the user across multiple computers while other people can use the setup normally, I would investigate anything tied to that user's Windows profile. Check roaming or redirected profile settings, display-management utilities, accessibility tools, and anything that could be changing sleep, display detection, or graphics settings. Testing with a completely new local or domain profile would be a useful way to isolate that.
Try changing the signal path as a diagnostic step. Run one monitor over HDMI and the other over DisplayPort, or bypass the dock temporarily with a direct connection. Some USB-C docks seem particularly sensitive to dual-DisplayPort negotiation, cable quality, or firmware. If the problem disappears with a different dock model, that would point to dock compatibility rather than the screens or laptop.
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