| Electronics > Projects, Designs, and Technical Stuff |
| ATmega2560 board overheating any idea's |
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| thinkfat:
BTW, the board was on external power while it went hot? How high was the voltage? Don't go too high on these linear regulators. You mentioned there's 70mA going into the 5V rail. That'd be 350mW, which is a bit much for just an ATmega. But anyway, if you tried driving the board e.g. from 12V, the LDO would have to burn up almost 500mW. No wonder it'd get hot. I think the problem is maybe not the 5V regulator but something connected to the 5V rail. |
| HendriXML:
I tested 3 power sources: 1) usb on laptop, resulting in overheating very fast and ongoing 2) psu, 5V at 5V in/output: current draw 70mA 3) powerbank via usb, no overheating If I remove the regulator I can test wether it even works. I know it had a valid usb connection before, but that got broken each time. I think the usb power was shutdown, but thats just guessing. What I don't understand is why the 5V regulator only in one situation dissipates that much. |
| HendriXML:
I've taken off the 5 regulator. And now it doesn't become hot any more!! Kidding.. I now can upload script to it, and have blinky working, yay.. To desolder it I took some thin wire under the 3 pins to add some tension. That way they became loose from the pcb after heating them up with a normal solder tip. Maybe there are better ways but this worked. The current draw is about 60 mA. I don't think something else is wrong with it, but I may be wrong. The current is a bit high as said, but there's also the usb chip, the 3.3 volt regulator, 2 leds (one blinking). Maybe the script that ran at it was a bit more consuming as well. It certainly wasn't the normal blinky. Thanks for the suggestions! |
| SiliconWizard:
Don't overclock your Atmega's!! :-DD |
| HendriXML:
I've read that the 168 and the 328 can run at 20 Mhz, so they are mostly underclocked :popcorn: I know these aren't powerful processors, but one can still do lot of stuff with them. I really like the smaller "pro" board, but mounting one in a box is not trivial. There are 2 large holes, not near center of gravity, but at a location that, eh.. had some room left I think. But why make them so big, how large of a screw does one need to bolt this down. Why not have 4 smaller holes? Will have to think about this. The idea is to use the photo to get the right dimensions. Have to see wether a reliable workflow can be constructed for that. Edit - in Fusion 360 one can have 2 points in a canvas image and set the distance in reality between those. After that, it is on scale. That makes it easy to locate the centers of the holes with high accuracy. (I hope) The photo should not have significant perspective errors then. |
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