How to Repair your Envision EN-7100si Flat-Panel LCD Computer Monitor

This article covers the repair for a relatively common problem with this computer monitor, where the monitor will turn on, but only display a screen for about half a second. Shining a bright light source onto the screen will reveal that the image is there, but the backlight is off. Two capacitors in the power supply have gone bad. Anyone with basic soldering skills should be able to perform this repair, and the cost is quite literally a fraction of buying a new monitor.

Difficulty: Moderately Easy

Instructions

Things You'll Need:

• Envision EN-7100si Monitor
• Soldering Iron
• Medium (PH1) Philips Screwdriver
• Medium Flat Screwdriver
• One 1,000-microfarad, 16-volt polarized capacitor
• One 470-microfarad, 16-volt polarized capacitor
• Some patience

1. 
    
   The cable screw that needs to be removed is circled in red.

   Remove the back cover and metal shroud under it. There are a number of screws around the outer edge of the back cover. Once you remove those, you'll need to gently pry around the edges of the cover with the flat screwdriver to pop it off. Once you have the back cover removed, you will see a metal shroud covering the electronics. There a re a few screws holding this down as well. Remove the screws and then slide the shroud slightly to the right to remove it. NOTE: There is a black cable running from the monitor's control panel into the shrouded area. You'll need to remove the small screw grounding it to the monitor chassis to unplug it from the circuit board under the shroud.

2. 
    
   The two capacitors needing replacement are circled in red.

   Locate the bad capacitors. There are two, both on the main (left-side, tan) power supply circuit board. There is a yellow transformer near the top of the board; one of the capacitors will be above it, and the other will be slightly to its left. One is part number C924 (1,000 mfd 16v) and the other is number C922 (470 mfd 16v). Both capacitors will probably have a slightly bulging top.

3. 
    
   The top capacitor is the new 1,000 mfd 35v replacement. Middle is a suitable exact replacement. Bottom is the bad one.

   Remove the old and install the new capacitors. You'll need to use your soldering iron to remove the old ones, from the bottom of the board. There are several screws holding it down. Be careful when removing the board so as not to damage the two connectors attaching it to the green video board. You should have enough solder still on the board to re-attach the new capacitors; if not, you can use a little more solder. Remember, when replacing capacitors, always use the same microfarad value and the same or higher voltage. I replaced the 1,000 mfd 16v capacitor with a 1,000 mfd 35v one in my monitor with no problems. Be sure to install the capacitors with the correct polarity, just as you would with a battery. The wide gray or white band on a capacitor is the negative side. The positive side is marked on the board.

4. Replace the power supply board, metal shroud and back cover. Make sure that when you replace the board, the two connectors attach to the video board. Remember to reconnect that black cable to its connector on the bottom of the video board as well. The metal shroud slides into place as before. Snap down and screw on the back cover, and you're done!

Tips & Warnings

• ALWAYS remember to install capacitors with correct polarity. Putting them in backwards will damage them and could damage your monitor.
• Always make sure that any equipment you plan on opening up is unplugged to prevent electric shock. The area you will be working in on this monitor carries active high voltage when it is plugged in.
• You should wear long pants and sleeves to prevent accidental burns if you are inexperienced with a soldering iron. Always replace the tip into its holder when not in immediate use.