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Big problem with my Launchpad


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I have received the launchpad from the online TI store 3 days ago. I've uploaded the led blinking sample program to the microcontroller using CCS and it worked. I've unplugged the launchpad, did something else and came back a few hours later to play with it some more. When I plugged the launchpad, I noticed that win7 didn't make the usual sound when a new device is connected. Then I tried reuploading the same code to the microcontroller just to see if it was detected, I got the message "No USB FET was found". I then tried to unplug the launchpad, but the temperature was very high and it burned my hand. I couldn't even touch it. I unplugged the cable from my computer. I tried it on two other computers, and the launchpad got very very hot in less than 5 seconds after I had connected it.

 

What can I do ?? I just received it 3 days ago :(

 

EDIT: I also tried to power it up with a 5v external bench psu, same problem, gets VERY hot (almost burning) after 5 seconds more or less.

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I connected Ground to the GND pin on the bottom right and +5V to the VCC pin also on the bottom right of the board.

 

1has20.jpg

 

This is the chip that gets VERY HOT almost instantly after I plug in a power source. I can't touch it or else I'll burn my finger.

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Hello, thank you for your fast answers

 

Yes my usb port is working fine I am now writing this post with my keyboard connected to the same usb port that I used to connect the launchpad. I am trying to see if any pins are shorted out on the LaunchPad but honestly I don't know how this could be the case since I haven't soldered anything and it isn't connected to any wires and stuff like taht.

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Don't connect 5V to VCC (the 3 pin connector), that's an unregulated power pin and should only be given supply voltage for the chip. I don't know the valueline chips that well, but I'm assuming 1.8V to 3.6V.

 

I killed a chip recently putting 9V to it for an extended period and the chip itself is acting just as you are describing. Any voltage to the regular VCC just makes the chip hot. Have you tried using the other DIP that came with the launchpad? I'd put it in and plug it in, that will confirm it's not the target chip; or is.

 

Check VCC with a multimeter as well to make sure it's within spec and not the cause of the problem.

 

Sounds like just a bad board. If nothing works, I would just call the TI helpline. They might send you a replacement.

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Sounds like a short to me, either on the board or inside the chip (ESD damage?)

I think you will spend more time troubleshooting it than it is worth, but start by removing MCU and all jumpers and see if that makes a difference. If not, take a magnifying glass and look around, you may find some unwanted piece of solder.

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Don't connect 5V to VCC (the 3 pin connector), that's an unregulated power pin and should only be given supply voltage for the chip. I don't know the valueline chips that well, but I'm assuming 1.8V to 3.6V.

 

I killed a chip recently putting 9V to it for an extended period and the chip itself is acting just as you are describing. Any voltage to the regular VCC just makes the chip hot. Have you tried using the other DIP that came with the launchpad? I'd put it in and plug it in, that will confirm it's not the target chip; or is.

 

Check VCC with a multimeter as well to make sure it's within spec and not the cause of the problem.

 

Sounds like just a bad board. If nothing works, I would just call the TI helpline. They might send you a replacement.

 

Well the problem started with the USB connection. I hooked up the external power source once this problem started to see if the USB port is the problem. Also, I have now completely removed the microcontroller from it's socket and the problem persists. The TUSB3410VF chip gets burning hot 2 seconds after I connect the usb cable.

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It's really strange that it worked fine, and then it didn't later, even though you didn't make any changes. I'd be looking close at the pcb for a short as someone else mentioned. Maybe the board got bumped and bent a pin, or a loose flake of metal/solder is bridging a connection. Running an old toothbrush over the pcb could dislodge a hard-to-see flake of metal.

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I agree with RobG: You will spend way more time troubleshooting than it's worth (you probably already have). Call TI and see if they'll replace it. If not, they're only $4.30, and shipping is currently free!

 

When you hit $4.30 worth of frustration, quit and buy a new one. Heck, buy three in case you do manage to damage one. Buy a Capacitive Touch BoosterPack or two while you're at it. $20 will go a long way with these TI kits, that's one reason I love 'em! :D

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  • 3 weeks later...
  • 1 month later...

I think I just had my first Launchpad die after ~6months due to this issue. The regulator and the TUSB chip get hot and the board is no longer recognized as a USB device. The interesting part is VCC is now down to 3.3V from the original 3.6V. It seems that the TUSB chip may have been damaged internaly and is drawing too much current. I wonder how many other lauchpads have suffered this fate. One thing I noticed when reading the Datasheet on the TUSB3210 is that 3.6V is the maximum rated input voltage. I wonder if some parts are getting cooked to death over time.

 

The good news is that right now the e-store is not charging for US shipping, so I ordered two spare boards for now. I just hope my Fraunchpad does not blow up too quickly once mspdebug starts to work.

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