have an arduino mega 2560 and when I connect it to my computer(M1 max Mac Studio) with a usb b cable Amazon.com: Amazon Basics USB-A to USB-B 2.0 Cable with 480 Mbps Transfer Speed for Printer or External Hard Drive, Gold-Plated Connectors, 10 Foot, Black)) the port button is greyed out. I have got the ch340 driver. When I first got the board I connected it to 12v power and it got very hot. The orange light started to get dimmer. I unplugged it from the power and have been using either just usb power or a 9v power supply. When connected to the 12v the orange light was solid, and when connected to 9/5v it is blinking.
An official Mega has a green power LED and 3 yellow LEDs (L-LED, Rx LED and Tx LED). So it's not fully clear what the orange LED is.
An official Mega does not use the CH340 serial-to-USB converter. Do you have a clone with CH340?
What did get very hot? Main processor? Power ICs (5V and/of 3.3V)? Other? To what was the 12V connected to?
Over-voltage can do permanent damage. So if 12V managed to get to the 2560, the serial-to-usb converter or the LMV358 opamp those components can be damaged. It might however not result in immediately observable problems but the damage might worsen over time and get to a stage where the damage is observed.
Based on your description (getting hot) I think that that has happened.
1 Like
The circled area is where it was hot. It is a genuine mega 2560 (not a clone)To my knowledge the board should be able to handle 12v( at least for a short time). It looks like it is the L-led that is flashing now on 9v, but was solid on 12v. The 12v was connected to the barrel jack.
What was supplying the 12V power, exactly? Please be precise. The more details you supply, the fewer we have to guess.
1 Like
The circled IC is the 16U2 (so no CH340 driver needed). That IC is responsible for the communication with the PC and seems to have died.
If this is a new board / under warranty, ask for a refund: something is not right.
I think you were right, the adapter is a/c out not dc so that probably fried the board
Thank you everyone for your help.
1 Like
12VAC RMS is about 17VAC peak.
The M7 diode is good for 1000V reverse, with < 1.1V forward voltage drop.
But the LD1117S50 5V regulator is only good for 15V.
You exceeded the maximum input voltage on the 5V regulator by just enough. You'd have probably gotten away with a 9VAC regulator.
This topic was automatically closed 180 days after the last reply. New replies are no longer allowed.