RUMBA board shorting out

[stridera]

Ok, now I'm kinda annoyed. I just plugged a raspberry pi into the 3d printer. Octipi started up and I was able to control it and view the print via the camera. I was all impressed.

Until I turned off the printer and then turned it back on. Now my raspberry pi is dead. wtf?

Maybe I need to hook up my power supply to my oscilloscope and see if it's throwing really dirty power along the rails. Whatever's going on, it's getting expensive. At least it didn't short out the rumba board again...

[Mjolinor]

That sucks but I think the Raspi has protection provided you went in over USB power and not directly.

[stridera]

The board was connected to the wall using a 1a microusb wall adapter. I've had the raspberry pi running on this power for a good two weeks with no problems before I decided to switch it over to be used on the printer. The RP was connected to the 3d printer via a standard usb cable.

My idea is that there is a floating power source or something that is throwing a current back down the usb cable from the rumba board. (I'm thinking this is what shorted out the rumba the first couple times because my hub has better overcurrent protection and it was creating some type of feedback loop.)

Since this has happened with a few boards and I don't see any complaints of rumba's shoring out other peoples parts, my next guess is the power supply doing something funky...

I'll hook up my oscilloscope later today and see what it shows me.

[BLKKROW]

I purchased the same DC power supply as you and my printer and Rumba will be here on Friday.

If my board burns out then we know something may be wrong with the power supply.

[stridera]

For your benefit, I hope that's not the case.

[BLKKROW]

For your benefit, I hope that's not the case.

+1

I just hope you get it figured out.

[stridera]

Just to update. I hooked my oscilloscope up and it seemed to be a pretty steady voltage line. I also checked again with my multimeter and received pretty close to a perfect 12v output. Still not sure why it's shorting out everything.

I bought a new raspberry pi and I'm getting a 12v->5v converter that I'm going to hook up to the power supply itself. So they'll all have a common ground This should protect it. Lets hope.

[Mjolinor]

With it unplugged measure the voltage from the case on both computer and printer with a DVM.

With them unplugged from each other I mean but with both powered on.

[stridera]

What do you mean? I measured the power coming from the printer power supply and it's 12v. That's what's being supplied to the RUMBA power rails.

The Raspberry Pi was receiving the usual 5v1a usb power. I'm wondering if the data line from the printer is over 5v, but that's hard to test w/o plugging it in a new raspberry pi... and possibly killing it. :/

[Mjolinor]

If damage occurs when the USB is connected it is often caused by a large difference in earth potential.

Measure with a digital voltmeter between your computer case and hte printer case. If ther eis a difference in potential then you have a problem, it should be zero volts but often isn't. If it is not then you need to look at your earths and earth paths to see where the problem is.