Faulty Neovo Monitor

[ih125]

I was delighted to find this http://www.edugeek.net/forums/hardware/68342-neovo-e-17da-monitor-repair.html but disappointed that the link from Webman's initial message is now dead. Is there another link available or does anyone have a copy of the document in a form they could send me?

Sorry to have to start a new thread, I attempted to post a reply to the above but the post a reply button hung on each attempt.

 

Best wishes,

[webman]

Hi ih125. Sorry the link is dead. I didn't get opportunity to save it before Posterous closed down, and I had no idea the article was as useful as it was (Google shows it referenced on several forums, including one in Russian...).

 

Someone else asked about this last year, and I managed to find a part-archive of the post. Here is what I've managed to salvage:

 

Nearly all (over 300) of our monitors are AG Neovo E-17DA models. Over time, we have identified two recurring faults with them:

 

• Monitor doesn't power up.
  
• Monitor displays image for half a second before disappearing.
  

 

Our problematic monitors were originally repaired under warranty, but now we have a large number that are no longer covered. Having nothing to lose, we set about attempting to repair these ourselves, saving us £130. This post will hopefully serve as a reference to rectify these two problems but comes with no warranty. We take no responsibility for any results after following the guide here. It works for us - please exercise caution when carrying out repair of any electronic equipment, and only continue if you feel confident enough to do what is required.

 

1. Start with the monitor face-down on a clean flat surface that won't scratch the display, with the top of the monitor closest to you.
   
2. Unfold the base stand and remove the two large screws that hold it in place.
   
3. Push the base out.
   
4. Remove screws on all 4 corners of the display.
   
5. The cover is still held in with about 3 clips on each side - start with the side where the headphone jack is. Insert a suitable flat screwdriver, strong butter knife (or similar appropriate tool) above the socket and twist to prise the top off - it will unclip.
   
6. Carry on until the "top" of the monitor is the last side, and just lift the cover away from the monitor.
   
7. Remove all screws from the metal shield and remove it. This is where the problems are.
   
8. First, detach the 4 lamp cables from the side. These are coloured blue, black, pink and white.
   
9. Then remove the two cable connectors from the logic board that connect the inverter to it.
   
10. Remove the two screws from the inverter board, and also the one screw from the logic board that also holds down a bracket for the inverter board.
    
11. To one side, lift away the inverter board.
    

 

 

Problem 1 - no power

 

This is caused by a bad solder joint on the main coil at the bottom-left of the inverter, and just requires re-soldering. It will have a small crack between the solder and the pin, and in some cases is only just visible with the naked eye - use a magnifying glass. It's most visible in photo 9.

 

1. Place the board with the component side downwards. Locate the solder joints for the coil - just next to the rubber pad (if it remained stuck to the board).
   
2. Apply some flux to the joint, and heat up with soldering iron.
   
3. Apply solder and soldering iron.
   
4. Repeat previous two steps once more if necessary to achieve a good joint.
   
5. It might be a good idea to re-do the other joint next to it while the opportunity is here.
   
6. Re-attach the two connectors from the logic board as well as the 4 lamp wires.
   
7. Insert one of the screws on the logic board.
   
8. Apply power supply to connector and test that the monitor turns on.
   
9. If this is the only problem, the "Check video cable" message should appear and remain there for several seconds.
   
10. Congratulations - it works!
    
11. Re-assemble the monitor - screw in the inverter board, the shield, the cover, and the base stand.
    

 

 

Problem 2 - image disappears after half a second.

 

This is due to 4 failing (or totally failed) capacitors on the inverter board.

 

This is indicated by one or more the capacitors bulging or having dark lines at the top of the components - see photos 5 and 6.

 

The failed ones need to be replaced with ones of equal value or higher. It's good practice to replace all of them - there are only 4 of them; and each set of capacitors will cost under £1 from Rapid Electronics.

 

The values are as follows:

 

• C41: 1000uF 10v 105c (Rapid code: 11-1542).
  
• C43: 470uF 25v 105c (Rapid code: 11-1546).
  
• C5 & C6: 220uF 25v 105c (Rapid code: 11-3704).
  

 

1. Remove the inverter board as described above.
   
2. De-solder and replace one capacitor at a time - here's a good guide on desoldering components - Desoldering
   
3. When soldering in the new capacitor, making sure its polarity is correct.
   

 

 

I also have the original unedited photos but they may not be that helpful out of context and without annotations.

 

Good luck!

 

Craig.