Arduino Mega 2650 won't do nothing

I think my arduino is bricked or something as when I connect it through USB the power "ON" light turns on, the "RX" light turns on and the "TX" light turns on. All three lights are on constantly the "L" light never turns on.

What could be the problem and how can I solve it?

Thanks

Does it work though? Can you upload a sketch and if so does it work? Eg if you load Blink, does the L led blink?

My computer doesn't detect the Arduino like it used to.

go to start menu/control panel/System/Hardware/Device Manager and click the '+' beside the Ports (com & LPT) section.. is the MEGA2560 listed as a connected device there? if so note the COM port number and set it in the tools menu of the Arduino software and then try to upload the 'Blink' Sketch

oryanorourke:
go to start menu/control panel/System/Hardware/Device Manager and click the '+' beside the Ports (com & LPT) section.. is the MEGA2560 listed as a connected device there? if so note the COM port number and set it in the tools menu of the Arduino software and then try to upload the 'Blink' Sketch

Again its not listed there.

Your original post implies you may have been powering the Mega with a source other than the USB port. If so, how?

do any unknown devices occur anywhere in the device manager?

This would indicate driver issues… otherwise you may have a bad component on the board… I am having a similar issue with one of my 2560s (see previous post…) I suspect the MEGA8u2 chip on my board which handles the USB to serial protocols was damaged by a short in a bad cable or something.

SurferTim:
Your original post implies you may have been powering the Mega with a source other than the USB port. If so, how?

Yes I was powering the arduino with a 12v car battery.

oryanorourke:
do any unknown devices occur anywhere in the device manager?

This would indicate driver issues.. otherwise you may have a bad component on the board.. I am having a similar issue with one of my 2560s (see previous post...) I suspect the MEGA8u2 chip on my board which handles the USB to serial protocols was damaged by a short in a bad cable or something.

Is the MEGA8u2 the chip in the middle of the board as i think it looks a little burnt. I have been running the arduino for a couple of days with a car battery no problem (positive to VIN).

The 8u2 is the small square one oriented diagonally near the usb jack... It sounds like you may have fried the controller.. the big one in the middle is the MEGA2560, the heart of the beast! Car batteries offer up much higher current than regular nine volts or regulated wall-warts...

see: forum.arduino.cc/index.php/topic,13345.0.html

oryanorourke:
I am having a similar issue with one of my 2560s (see previous post...) I suspect the MEGA8u2 chip on my board which handles the USB to serial protocols was damaged by a short in a bad cable or something.

...or was damaged by using a power supply less than 6.6 volts on Vin, or powering the Mega with the 5v bus and the USB power at the same time. This has been known to brick the USB to serial IC on a Mega.

I haven't heard of using a dual supply (USB and Vin/power jack simultaneously) with a supply on Vin or the power jack above 6.6 volts bricking the 8u2 IC. What voltage do you measure on the 5v pin now? Is it still 5 volts? Maybe the main 5 volt regulator failed.

oryanorourke:
Car batteries offer up much higher current than regular nine volts or regulated wall-warts…

My understanding has always been that devices consume the current they need, and not that a battery that can provide higher current will force it on the consuming device.

My guess would be an over-voltage rather, since the 12V recommended may have been exceeded by a nominal 12V battery, especially if it was still connected to the charger. But the maximum allowed is supposedly 20…

Of course that is how ohm's law works.. but cars are not stable electronic environments.. high voltage transients and such are common.. the arduino would need to be protected from these events

oryanorourke:
The 8u2 is the small square one oriented diagonally near the usb jack… It sounds like you may have fried the controller… the big one in the middle is the MEGA2560, the heart of the beast! Car batteries offer up much higher current than regular nine volts or regulated wall-warts…

see: forum.arduino.cc/index.php/topic,13345.0.html

I don’t think the problem is with USB jack, because the 3 lights still light constantly when I connect with the car battery. I know that car batteries store high current but its still 12v as it is not connected to a charger/alternator.

What the problem can be is that I had placed a small breadboard on the middle chip of the Mega as it fitted perfectly and the chip overheated.

Could have that be the problem?

that sounds also likely.. if the breadboard was directly contacting the chip it could cause overheating and damage

oryanorourke:
that sounds also likely.. if the breadboard was directly contacting the chip it could cause overheating and damage

But why are the RX TX lights on?

Azzure:
I know that car batteries store high current

You can't store current: current by definition is the rate at which charge moves.... They can provide high current yes, but devices only take the current they need.

but its still 12v as it is not connected to a charger/alternator.

Nominally 12V, but did you measure it? I could have been more if recently charged. But as I said, 20V is supposed to be the max although 12V is the top of the recommended range.

So perhaps a combo of the voltage just on the safe threshold, or a wee bit over, and the breadboard keeping the heat in?

...and you checked the voltage between the 5v pin and ground? It is still 5 volts? More? Less?

Azzure:

oryanorourke:
that sounds also likely.. if the breadboard was directly contacting the chip it could cause overheating and damage

But why are the RX TX lights on?

The Rx and Tx are related to data transfer in and out of the controller and should only light when uploading or performing data transfer operations.. they fact that they are constantly lit upon power indicates even further that there is a serious component issue with your board and i think we have found the cause.. as jimbo stated, though the arduino is rated up to 20v.. it's recomended voltage for operation is 12V to allow a buffer for spikes and such.. my car battery regularly measures 12.7VDC.. combine this with the covered chip and i think the culprit becomes apparent

oryanorourke:

Azzure:

oryanorourke:
that sounds also likely.. if the breadboard was directly contacting the chip it could cause overheating and damage

But why are the RX TX lights on?

The Rx and Tx are related to data transfer in and out of the controller and should only light when uploading or performing data transfer operations.. they fact that they are constantly lit upon power indicates even further that there is a serious component issue with your board and i think we have found the cause.. as jimbo stated, though the arduino is rated up to 20v.. it's recomended voltage for operation is 12V to allow a buffer for spikes and such.. my car battery regularly measures 12.7VDC.. combine this with the covered chip and i think the culprit becomes apparent

Is there a solution or do I need to buy another arduino?