HP L1906 LCD Monitor Repair Guide (Faulty Capacitors)

8 Sep

One of my users was complaining one day that her computer wouldn’t come on, the box was on but the monitor was blank. I rebooted the box and it seemed ok for a little while, then, about an hour later it happened again, but this time rebooting showed nothing on the monitor. I swapped over the monitor and it worked perfectly so it seemed to be the monitor at fault.

I had a play with the faulty monitor and no matter what I did, the green LED on the front would just flash, about once a second, if I listened closely enough, I could hear a high pitch noise, in time with the flashing LED. This led me to believe that at least one of the capacitors had blown, further reading revealed that HP had used quite cheap components in these monitors and this was a common fault.

So, I set about taking it apart, one of my favourite things to do. It’s pretty straight forward to get it apart.

(It is advised to leave it off for a while so any capacitors can discharge to make it safe to work on.)

•    Take out the 3 screws holding the stand in place
•    Take out the 4 wall mount screws
•    Take out the 4 Corner screws
•    Place it on a soft surface (you don’t want to scratch your screen)
•    Use a flat blade to release the silver plastic bezel
•    Unscrew the 5 screws holding the buttons circuit board in place
•    Un clip the 4 blue/black and pink wires on the side (I used a permanent marker with which wire went where to make it easier when reassembling)
•    Remove the 2 hex screws on the monitor port
•    Remove the 4 screws (2 on each side) holding the monitor in place
•    Remove the screws holding the kettle adaptor in place
•    Remove the monitor from the chassis and take out all connecting cables
•    Remove the 4 screws on the back of the power board and the 4 on the back of the input board
•    Disconnect the power board from the input board and move this component to another desk
•    You’re now looking for any capacitors (little black things, with markings like “CapXon 10V 1000uF” on them) that are bulging at all at the top. I’ve taken a photo of one that I removed and one that is new so you can see the difference. You can get replacements from Maplins or eBay easily and cheaply, I only replaced 2, but you are advised to replace them all whilst you have it apart.
•    Replace the faulty components and reassemble the monitor.
•    Plug it in, stand back and admire your handy work. Good job Sir!