Hi, I soldered together a Menta according to the instructions. The solder joints all look good. When I plug in external or USB power, the green power LED lights up. But when I press the reset button, nothing happens. (I understand from the instructions that the red LED should flash.) When I try to upload a sketch, I get the following error:
avrdude: stk500_recv(): programmer is not responding
How should I go about troubleshooting the device?

