I’ll cut to the chase quickly. I wired up my spatula with crocodile clamp on a string (tool length sensor) to the Ramps. I checked continuity and all my connections very carefully from sensor to the plug on the board and all checked out. I went ahead started the CNC, all good. I moved to position where I wanted to test the new sensor, still all as expected. I run my machine with Estlcam and wanted to test the sensor by monitoring the end stop indicator light in the Estlcam Controller. As soon as I tested the connection, my laptop shut down. I immediately disconnected the new sensor.
What I diagnosed so far:
-USB port on Laptop still works
-Arduino got recognized by Windows, BUT only when the CNC-PSU was off
-as soon as I plugged in the PSU, ma Laptop shut down again
-I disconnected my Laptop and begun testing connection and looking for shorts with my multimeter
-after hours searching I connected the PSU and started looking for wrong voltages or ANYTHING
…then the magic smoke from the ATMEGA 16u2 and the 5V regulator appeared (see Pictures). There is visible damage on the chips and I guess I need a new Mega^^
Maybe someone can point me to my mistake, I’m out of ideas.
Typically when you short power to ground you either blow a fuse, or blow a voltage regulator. This Instructable talks about fixing both, including a picture of the location of the voltage regulator and the fuse on the Mega board. Typically I use inexpensive clone boards and just replace a board if I’ve fired the fuse or regulator. Often when I blow a voltage regulator, the board still works when the USB is connected. Blowing a board has never impacted my computers USB connection, and it is highly unlikely that you hurt your Ramps board.
If the USB wasn’t plugged in, that 5V was only coming from the mega, and I would replace the mega. Since the usb was connected, your computer was smart enough to bail. But there may be other parts on the mega that are burnt. Hopefully the computer is fine. The ramps is probably fine.
