Princeton Graphics VL1918 monitor repair

The problem

My Princeton Graphics VL1918 monitor began turning on and off every second or two. It would cycle on, show the screen, then just as quickly turn off. Often times this was accompanied by a beep or a chime. It seemed most prevalent when it was waking back up from screen saver or power saving mode.

The cause

The cause of this problem is the failure of 1 (or more) of 3 capacitors that are a part of the power supply.

Tools needed

• Phillips head screw drivers.
• Flat tip screw driver.
• Soldering iron and solder.
• Wire cutter

Skills needed

I'm no electronics wizard at all. I was able to do this fix in less than one hour with my 3 ¹⁄₂ year old daughter helping me. Only basic tools and simple soldering techniques are required. There are a lot of steps listed below, but they are quite simple and detailed. This is a what have you got to lose repair that really works.

Cautions

• We are dealing with electricity here, so take the necessary precautions not to electrocute yourself or burn your house down.
• Please take written notes. It is all too easy to forget how something plugged into something else.

Credits

I learned about this fix on the FixYa website.

The fix

Replace the three capacitors with new ones. I don't know how to test the existing capacitors to see which one(s) went bad. And, given how inexpensive replacement capacitors are, I have no desire to fiddle with it.

1. Order 3 capacitors with the following specifications: 470uF 25V High Temp Radial Capacitor (470µF 25V). I purchased them from Amazon.com. I bought 9 of them and the total including shipping was less than USD $10.00.
2. Disconnect the monitor from the computer and the 110 power source. Remove both cables completely.
3. Lay the monitor face down on a large flat surface. You may want to lay a towel down beneath the monitor to protect the bezel.

   

4. Remove the 4 Phillips head screws that secure that stand to the back of the computer and set the stand aside.

   

5. Remove the 3 Phillips head screws that secure the bottom of the bezel.

   

6. Using a wide, flat bladed screwdriver, carefully pry the back cover off. It is made out of plastic, so be careful. It will pop off fairly easily. Once off, set it aside.

   

7. Note the rectangular center metal piece that is screwed to the main body of the monitor. This is the where the power supply is located.

   

8. There will be adhesive foil stuck around various locations on the back of the monitor. Lift it away if you can...or VERY CAREFULLY cut it if you cannot. CAUTION: There are wires beneath most of these foil pieces, so be very careful.

   

   

   

   

9. Make a note of where each wire goes.

   

10. Unplug all the wires.
11. Remove the 4 Phillips head screws that secure the rectangular center metal piece to the main body of the monitor. Withdraw the metal piece and set the main body of the monitor aside.
12. Flip the removed piece over so as to expose the circuit boards.

    

13. Pull off the clear plastic protective piece. Try to keep it intact as you will want to put it back in place during assembly.

    

14. The power supply circuit board is the one into which the power cord is normally fitted.

    

15. Remove the 4 Phillips head screws that secure the power supply circuit board in place. Note that one of the screws is different (designed to ensure a good ground connection). Note where it is located so you can return it to the same location.
16. Very carefully withdraw the power supply circuit board. It is connected to the neighboring board with a pin connector that slides out.

    

17. Identify the three capacitors. They are black with silver tops and have a gray stripe on one side that signifies the location of the negative post. The manufacturer is CapXon and the 470uF 25V (470µF 25V) specification is printed on the side.

    

    

18. Note the location of the negative post. The circuit board is also marked.

    

19. Using a soldering iron, unsolder each post from the board:
    1. Ensure the soldering iron is very hot.
    2. Hold the board in a vertical position.
    3. Use a finger to place light pressure on the capacitor as if you are prying the capacitor away from the post that you will be unsoldering.
    4. Touch the tip of the soldering iron to the post (on the under side of the board).
    5. Maintain pressure on the capacitor as the soldering iron heats the post.
    6. When the solder liquefies, the capacitor will pull away from that post.
    7. Repeat this technique for both posts on each capacitor.
20. Insert the new capacitors being sure that the negative post is inserted in the proper hole. The circuit board is marked. Or, you can refer to your notes.
21. Solder each post in place.
22. Trim the excess length off each post.
23. Reassemble in reverse order.
24. Test the monitor with the power cord only (no connection to the computer) before plugging it back into the computer.