Diagnosis
The monitor is experiencing a total power loss, indicating a failure in the primary power delivery system. Since there's no standby LED or any sign of life, the issue is isolated to the internal power supply unit (PSU) or the main logic board, not the video signal or backlight. Given the symptoms, a faulty internal power board or a blown fuse on that board is the most likely culprit, often triggered by a power surge or component fatigue.
How to Fix It
First, perform a full power cycle to rule out a temporary electronic lock-up. 1. Unplug the monitor's power cable from both the wall outlet and the monitor itself for a full 60 seconds. 2. While it's unplugged, press and hold the physical power button on the monitor for 15 seconds to drain any residual power. 3. Reconnect the power cable directly to a known-good wall outlet—bypassing any power strips, extension cords, or UPS units. 4. Firmly press the power button once. If the monitor remains dead, the problem is internal hardware.
If That Didn't Work
The BenQ EW3270U has an internal power supply, so external power brick swaps aren't possible. Your next step is professional repair. Contact BenQ support for warranty service or to locate an authorized repair center. A technician can safely open the monitor to diagnose and replace the faulty power supply board or mainboard. Attempting to open the monitor yourself voids the warranty and risks severe electrical shock from high-voltage components inside.
Heads Up
This type of failure is frequently caused by voltage spikes from the mains power. To protect a replacement unit or future monitors, always use a high-quality surge protector with a high joule rating, not just a basic power strip.