NerdKits - electronics education for a digital generation

You are not logged in. [log in]

NEW: Learning electronics? Ask your questions on the new Electronics Questions & Answers site hosted by CircuitLab.

Support Forum » Pretty sure something fried.

May 19, 2011
by Elementell
Elementell's Avatar

I was finishing up this, and plugging in the USB cord(at this point had not programmed it yet, it still had the default temp sensor program), and I must have knocked something out of place because weird random characters were showing up on the LCD. While checking the wiring I was constantly plugging and unplugging the battery to see if I'd fixed it. I left it on for a good 10 seconds when I smelt something similar to burning plastic, but not strong at all. I felt the 5v voltage regulator and it was really hot, and I quickly disconnected the battery. I tried the battery again, and noticed the LCD wasn't displaying anything. I'm pretty sure I either fried my MCU, or my LCD screen, how do I check? I really don't want to pay for another one of these T.T, just when I thought I got a grip on the programming too...

May 20, 2011
by Rick_S
Rick_S's Avatar

Well, you can somewhat check the micro by trying to send a program to it when correctly wired w/o the LCD. If that works, try building the led blink project to see if it'll blink an LED. If you either can't communicate with it, or the LED won't blink when all is wired correctly, you may have blown the micro.

If you determine the Micro is good, properly connect the LCD to see if it comes to life

If not, it could be bad. Of course all these checks will depend on how confident you are in your ability to build the circuit correctly.

You could have blown the regulator (although they are pretty resiliant) if it was dead shorted long enough.

Do you have a volt meter to test the output voltage of the regulator? You might want to do that before building anything else.

Rick

May 20, 2011
by Elementell
Elementell's Avatar

Actually, I just plugged in the battery ready to progam something, and the regulator still gets hot, but I learned something else. My MCU was actually hot enough to burn my finger rather badly, checking to see what was causing so much heat as to heat up the wires so much. I had a photoresistor plugged from the project I was working on and that was really hot too. I really don't know whats going on, because no wires are touching each other, and everything is the exact same as it was. even if my voltage regulator was broken, I don't even think 9 volts would really do this. Ugh, I don't know, but what I do know is I don't have a nerdkit anymore. No fair... At this point I know I've passed the point of no return as far as my MCU goes, but does anyone know what could possibly cause it to heat up that much in such a short amount of time? I'm legitimately talking 15 seconds max as far as how long the battery was connected for this to happen.

May 20, 2011
by Noter
Noter's Avatar

I once fried a couple of mcu's in about 5 seconds. They actually smoked. It doesn't take long at all.

If I were you I would pull the mcu and all components from the breadboard and see if I could just get 5v on the red rail via the regulator. Then put the mcu back in and see if there is still 5v on the red rail. Then every hookup, check that voltage again until you find the problem.

May 20, 2011
by Elementell
Elementell's Avatar

After it gets that hot its done right, its not going to work again is it? I checked the voltage regulator btw, it works fine. I completely took apart the breadboard, and since I fried my MCU I probably won't be getting another one for a while, so whatever. When I get another one I'll reassemble it with better wiring to make sure wires don't accidently cross or something. Can I test if my LCD is fried without a mcu?

May 20, 2011
by Noter
Noter's Avatar

It's not necessarily dead. I also had one get real hot because of bad wiring. I smelled it a little but it never really smoked. I let it cool down and it was ok, I still use that chip. So, you won't know for sure unless you give it a try. I haven't fried an lcd so I know less about that but go thru the steps and try it all again to be sure. It is amazing how much abuse they will take and still work. But be careful with your wiring and check with the volt meter often until you've had more practice and success.

Chips are not that expensive. You can buy a new chip from nerdkits for $6 and a new lcd for $15. Add some for shipping and you can probably have new parts for about $25. But check your old ones first as maybe they are ok.

Post a Reply

Please log in to post a reply.

Did you know that NerdKits also has extra parts available for its customers? Learn more...