Arduino Uno Problems

So with all of the searching that I have done recently I have found no results so here goes. When I plug my UNO r3 into USB nothing appears to happen no lights no blinky LED nothing. The board cant be written to by either. When I plug a USB debug cable into the computer and connect the VIN and Ground pins it lights up and if it is still connected to the USB I can even upload a program to it. However the power jack and the USB on board wont power the device. Any Ideas why this is happening and or what I can do to fix this? My only thought is that possible the voltage regulator had failed and I may try to replace it. Any other suggestions?

mheiger:
Any other suggestions?

Get a new one.

Well it isn't that I dont have other boards to use I just really like the uno and hate to buy something when i could fix what I have. also it works fine with vin and ground and that makes me think it is something simple.

It could be any number of things. There’s more than just a voltage regulator on there.

If the VIN powers the board, then the onboard regulator sound like it's working. If only from the USB connector doesn't power the board, then most likely the fuse on the USB power is blown. You probably can replace the fuse and hopefully nothing else is blown.

hiduino:
If the VIN powers the board, then the onboard regulator sound like it's working. If only from the USB connector doesn't power the board, then most likely the fuse on the USB power is blown. You probably can replace the fuse and hopefully nothing else is blown.

The fuse is a polyfuse so it fixes itself.

Depends how badly it was blown. I’ve seen others replace it to get it working again.