Computer not recognizing arduino mega?l7805cv

Suddenly today, my computer quit recognizing my arduino mega. I have a circuit built using an L7805cv voltage regulator to power the board, while I plugged it in with usb to update the program. I have done this previously without issue, but I'm not sure if maybe having the arduino powered by this power supply and plugging it in with usb caused issues.

My desktop and laptop are both running Windows 8.1, and both recognize my Uno, however neither recognize the mega. For the uno, windows beeps signifying that a USB device was plugged in, however that doesnt happen for the mega. Also, on my laptop, the mega shows up in Device manager as an Other device with a yellow exclamation, but does not show up at all in device manager on my desktop.

What steps can I take?

Edit: I was able to use an arduino nano as an FTDI, simply connecting the power, ground, reset, tx and rx pins between the nano and mega, and I could load sketches and view the serial monitor fine. SO is there an issue with the usb port on the mega?

iceng2 months ago

A lot depends on who is more powerful, the 5.0063v USB port or the 5.0024v L7805cv PS of your making, facing off each other in this solar system..