Arduino leonardo heating issue

My arduino leonardo is heating up....... I think i fried the voltage regulator. I had made many projects with my arduino earlier. When i accidently reversed VIN and Gnd when using a 7.4v 1400mah battery. The arduino is still working, but when i connect it to any power source, it starts to heat up. When I ran my hand across the board, i found that the voltage regulator was the source of the heat. The voltage regulator on the leonardo is ncp1117 the same as in uno. I can barely upload the blink program, by that time it will start overheating. Suggest me some remedies Should i replace the voltage regulator? If not, what else should i do to fix the board? Please help me


I suspect this thread will be moved to another place soon. Check the schematics (in PDF). It shows the presence of a reversed polarity protection diode (D1, M7), effectively shorting the power supply in that case. It is however very well possible that that diode didn't withstand the current delivered from the 1400 mAh accu (the design relies on the presence of a fuse in the power line), because its potential is much higher than 1.4 Amperes. I don't know of any diode by name of "M7", but you might be able to find out more about it and find a datasheet, so you can find out what current it would withstand. I would do a continuity test (the 'beep' with the multimeter) in both directions to that diode. If it is open (no connection at all in any direction), the diode must have died. If it is shorted (some or full connection in both directions), it has also died. Perform each test for a few seconds, because of the capacitor's influence. A short might also be a problem in the capacitor instead of in the diode. Next to the diode is a polarized capacitor, it does not like reversed polarity and it will be damaged to some extend after the diode has gone and the protection it was supposed to give, ended with the death of the diode. To some extend means you might not notice a defect, and it might keep on working more or less. But in case the diode has indeed died, you should also change that capacitor.

I can't tell you anything about the regulator (didn't research that one).

Thanks But In my case, the arduino is working. The only problem is that the voltage regulator heats up when powered. Since i noticed this defect, should i just change the regulator? Please help

You could try that, but some other components may have taken a hit. If you can remove it then you can troubleshoot it. Is the regulator still working (IOW, does it still put out 5V)? Polarized caps, esp. tantalums, don't take kindly to reverse voltage. Remove it and apply your external supply (battery) - any heat? With the regulator removed, and using an external 5V supply (applied to "5V"), is there any excessive draw on the supply or anything getting hot?