Dell u3014 monitor repair. Power on problem.

Última actualización: July 17, 2021

30 minuto - 1 hora

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Introducción

This monitor stopped turning on.

Herramientas

The u3014 monitor opens the same as most other recent Dell monitors.
First remove the stand.
Remove the bezel. This can be done by hand and a plastic knife. Approaching the screen from behind, peel the bezel with your fingers (photo).
The rest follows quite easily, but in the corners you might need to insert a blade or similar to pry open the clips.
When removing the bezel, be careful with the control panel (stuck in place with glue, covered with glued-on strip) and power-button (2 screws).

Remove the connectors. Black cable to backlight (push clip and pull). Two multi-color cables to LCD (push in the sides and pull). Power and control ribbon (pull). USB hub power (push clip and pull). USB ribbon (lift flap and remove).
The frame with PCB is held in place just by metal tape.
The USB hub is completely loose.

Caution: The circuit board contains capacitors (they look like cylinders) that can shock you if they discharge. Be careful not to touch them as you work. If possible, use a capacitor discharge probe to safely rid the capacitors of dangerous charges.
To solve power on problems, inspect the board. In my case there was a cold solder joint that actually showed a little spark when plugged in (photo Q816). Re-soldering fixed it. Your case might be harder to find and fix.
Many repair guides talk about replacing all capacitors rather aimlessly. In this monitor they used Nichico caps which are very reliable. So that is an unlikely fix.
Be extremely careful fixing these switching power supplies, even more so in Europe where one has 230V. Discharge capacitors etc.
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If things are unclear, leave a comment.