How I fixed my Lego Mindstorms NXT Robot - flickering screen no more!

I've been teaching robotics using the Lego Mindstorms NXT (and previously the RCX ) robotics system for a number of years now. I usually have four NXTs and multiple storage bins going at anyone class. Typically the classes and summer camps are sold out with a maximum of eight kids, so they team up two to a Mindstorms robot.

Most of the time everything goes well but occasionally the kids drop the robots. The Lego Mindstorms NXTs, which are the brains of the system are rather rugged but they are made of circuit boards and the LCD screen is glass so they can break if really abused. I had one kid who seemed to be having problems at home take his frustration out on one of my Mindstorms NXTs - he purposely slammed it to the floor. The NXT didn't totally break but the screen started to flicker. You still could program it and run it but you couldn't always see what was going on, on the LCD screen of the NXT.

I tried upgrading the firmware and other software solutions and eventually gave up and bought another unit. Its tough when you are basically volunteering your time to have to spend all of the money you do earn on equipment.

Here is the fix that worked for me. No promises that it will work for you and I suggest running through all of the resetting and firmware upgrade fixes before attempting any soldering on your unit.

The Mindstorms NXT Fix - Step by Step

1. Remove casing (remove batteries and four screws in battery compartment)
2. Remove two daughter board screws
3. Separate daughter board from main circuit board
4. Separate daughter board (green) from white support board
5. Pull daughter board away from LCD and flip up to expose surface mount capacitors
6. Touch soldering iron to solder joints to resolder
7. Reassemble and test

In my own experience I had to redo this procedure a few times. I also touched C4 in addition to C1 - C3. Good luck! Photos below plus a step by step video from Javapda on how to solve the flickering screen problem on the Lego Mindstorms NXT.

Now keep in mind there are not guarantee that this will work or that you will do it properly or not damage the NXT permanently. But if you have a non-working NXT this method is worth the risk before buying a new one. Lego should really have issued a recall on this product in my opinion as it is a common problem and should be considered a faulty product. I had a RCA TV once that had a similar weak soldering joint that caused thousands of TVs to fail. RCA to their credit issued a recall so customers could take their TVs in to repair shops to get fixed.

If you have any doubts about your ability to solder small parts, you might consider taking the NXT unit to a local electronics repair shop with these instructions. Maybe for a charge of 15 minutes of work they will be able to revive your NXT.

Copyright Edward M. Fielding