I turned on my NXT the other day. It went pop and smoke appeared under the LCD panel. I opened her up and found the 2200 uF capacitor looked like it blew out some material. There is a hole around one of the leads. I tried testing it with a multimeter and I don't see the resistance changing over time like the other capacitors.

When I turned on the NXT again, the LCD displays random moving lines. Has anyone experienced a similar problem with their NXT? Is it repairable?

LEGO NXT Repair? by dr_spock_888, on Flickr

LEGO NXT Repair? by dr_spock_888, on Flickr

Edited August 30, 201410 yr by dr_spock

Blown capacitor. They have a tendency to swell at the tip with time/use. You can replace it or get it replaced by someone who's familiar with electronics. It doesn't guarantee that it will fix the problem. I'm not sure if TLG will assist you in this since you opened up the unit. Good luck.

That is not common problem, but it happens. Unfortunately now that EV3 has taken place of NXT you cannot go to costumer service. I would not waste time trying to fix it. But rather go get a new one on eBay, or you could upgrade to an EV3. I have never heard of smoke coming out of the brick, very odd.

If it were mine, I'd consider it toasted and get an EV3. But before that, I would use this as an opportunity to see if I can solder a new 2200 µF cap in its place and revive it.

(Note: It may be related to an existing issue or have created another issue.)

Edited August 31, 201410 yr by m0dulo

it is very easy to replace such a component for everyone with basic skills in electronics / soldering

A member from HispaLUG COULD go to customer service last week but he had to send his NXT unit. He also had an LCD failure but the unit itself worked. He was given a new NXT unit.

Lego may help on this. I have had nxt replaced in the past. Ther still sell them so have stock give it a go. Failing that to swop the cap is a simple task, and they are cheep as well

Contact Lego customer Service and ask what they propose. Before doing anything yourself, you might still get a replacement through them. Probably free as well.

When I had problems with the display of my unit I received a complete new unit.

Edited September 1, 201410 yr by Balrog

just do it,use this as an opportunity to see if I can solder a new 2200 µF cap in its place and revive it.thanks

Edited September 1, 201410 yr by bingfters

I teach with NXT bricks, and got some of the original ones with bad caps. About 17 of 22 screens died. LEGO replaced them all, no questions asked. Contact Tech Support. They will probably help.

About 17 of 22 screens died. LEGO replaced them all, no questions asked. Contact Tech Support. They will probably help.

Afaik, the first version of the NXT brick has this pretty common issue with the display. That's just what happened to mine as well. I believe the intelligent bricks from the NXT 2.0 sets are not affected by this. Also, what you described helped me as well. Replacement without problems.

I use to change caps on motherboards... Some started working and some didnt... Its a gamble. I'd suggest contacting Lego and if they send you replacement without you having to return the defective one you can still try change that cap.

I thing you have to return it or people like me will ask for a free one

Thanks for the advice, everyone. I'll try LEGO customer service and see what they say. I don't have the original purchase receipt anymore. It's not hard for me change out the capacitor myself. I found a local place that sells them for less $1 each.

Lego may help on this. I have had nxt replaced in the past. Ther still sell them so have stock give it a go. Failing that to swop the cap is a simple task, and they are cheep as well

Did you have to pay for shipping of the NXT back to LEGO?

Did you have to pay for shipping of the NXT back to LEGO?

When I got my NXT exchanged, I didn't have the original receipt either.

You have to pay for shipping the NXT to them. But if they give you a new device, that's probably a worthwile "investment" ;)

Yes, you pay back to them then then send to you for free. Was a really good service. All in the uk

LEGO service is awesome. They're sending a replacement NXT. They're also sending a SASE to return the bad part.

As expected ;-)

They really are the best, good job Lego

Wanted to say thanks to all for this post. Last week, my NXT 2.0 brick popped and started smoking after I put fresh batteries in it. I found this post, contacted LEGO customer service using their online form, and got a call on Monday the 19th (a holiday in the US) that they had already prepared a new brick($170) for shipment and would be sending along a prepaid envelope that I could use to return my damaged brick. They didn't ask for any proof of purchase at all. They just called to let me know they were concerned about my experience, that LEGO engineers would look at the brick and that I a new one was on the way. I got a shipping confirmation from LEGO for my brick this morning. Honestly, I can't remember a better experience with customer service at any company.

Anyway, thanks again. I had planned to take it apart and attempt a repair. While that would have been fun, I'm happy to just have a new one! :-)

That's encouraging. I contacted them recently but wasn't holding my breath... Here's hoping :)

Just got an email to say that they are sending a new unit (faulty screen). Great service so far given that I bought mine second hand. I'd strongly recommend getting in touch with them if you have any troubles at all.

Edited February 10, 201510 yr by OzShan

Just got an email to say that they are sending a new unit (faulty screen). Great service so far given that I bought mine second hand. I'd strongly recommend getting in touch with them if you have any troubles at all.

Lucky you. I got a reply saying that it's not under warranty because they stopped producing them in 2006.