# Specific 3D Printers, Scanners, & Hardware > RepRap Format Printer Forum > MakerFarm Forum >  RUMBA board shorting out

## stridera

I purchased my Makerfarm i3v 12" a few weeks ago and set it up.  I was able to attach the board to my computer via USB (Jumper on USB POWER) before hooking it up and program it no problem.  I then switch the jumper to standalone and plugged it in. The display worked and the motors all moved correctly.  However, as soon as I attach the usb cable to the board to begin printing stuff it shorted out and I had to get it RMA'ed.  (It wouldn't turn on after that and even after disconnecting everything and returning the jumper to USB power the computer said the usb device was drawing too much power and turned off the port.)

I figured it was something weird with the board, but I just did the same thing with the RMA.  Hooking everything up works fine.  All the motors move, display works, everything handles correctly.  However, the moment I hook it up to the usb port while it's on standalone, the board fries and now nothing works.  (Hopefully I'll get another RMA.  I would understand if they deny me.)

Anyone know what I'm doing wrong?  Are the RUMBA boards not supposed to be attached to a computer while printing?  Am I supposed to keep it on USB power if I have the usb cord attached?

I really don't want this to happen again.  Any advice would be appreciated.

I'm using this usb hub:  http://www.ianker.com/product/68UNHUB-B7U  The hub works great and I never have a problem with anything else.  I've been charging my phones and tablets with it forever, and I have my webcam, mouse, and keyboard plugged into it.  Everything works fine until I plug the rumba board in.

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## sniffle

honestly, i've never heard of that happening, tsteever, and a couple others have a rumba board... hopefully they chime in... also i would suggest hitting up irc,

on freenode there is, #reprap, #marlin-firmware, ##MakerFarm, and #thehotend

reprap is a good all purpose channel, they can generally point you in the right direction or point you to who you need to talk to
the others are fairly obvious other than thehotend which is a new channel that timmytechtv from youtube has started, still getting off the ground with only a few people in it, but they are fairly nice

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## tsteever

I had a weird power issue when moving back and forth between the ABL setup. It turned out I had the endstop switch hooked up wrong after rewiring it. You say everything moves fine until you hook up the USB? I do most of my printing through the USB port. 

The endstop switches have a 3 plug jack that can be plugged in wrong. My suggestion is to check that the endstop switches are connected correctly. The only time that I had my board give me trouble is when i had the endstop hooked up wrong. I had the plug shifted down one too far. It was on the right set of jacks, just shifted so only two of the three pins were plugged in.

If it works fine and everything is hooked up right then I am at a loss. I am still learning a lot about this stuff. What kinda voltage are you getting to the board?

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## Draud

I have never had a problem with my Rumba board but I have mine directly connected to my PC with no hub. I would triple check all you wires to make sure that everything is wired properly. Then I would bypass the hub and hook it up directly to the PC. Could be the current from the powered hub messing with the board.

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## tsteever

Yeah, check the hub. I hook up my board directly to the computer.

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## stridera

I've followed the wiring guide.  Colin from Makersfarm has been awesome so far in attempting to help me.  I took a bunch of pictures and he says everything is setup correctly. 

I have 12v running to the board.  Everything is wired as the diagram suggests.  Just attaching the usb fries the board.  That' all...

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## tsteever

Even attaching usb directly to the computer? No hub?

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## tsteever

And when you say fried, as in ruined? My rumba just shut down. As soon as I corrected the endstop it turned back on.

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## stridera

Fried.  Screen dies and nothing happens.  After disconnecting it and removing all components, the first one said it was pulling too much power and shut down the usb port.  Second one won't even recognize a device is plugged in.  Very dead.

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## Draud

What kind of power supply are you using?

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## Chadd

I print everything on my 12" with Rumba board from the PC through a direct connect USB. Double check all your connections and wiring I am guessing you have a wiring issue. Either that or there is something up with the USB hub or a device plugged into it may be back feeding power somehow?

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## stridera

I'm using this power supply:   http://amzn.com/B00D7CWSCG

It's set to exactly 12v based on my fluke multimeter.

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## Chadd

> I'm using this power supply:   http://amzn.com/B00D7CWSCG
> 
> It's set to exactly 12v based on my fluke multimeter.



That is the same power supply I use.

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## tsteever

Ditto. I may have missed it, but have you tried just plugging in the board straight to the computer? No USB hub? Or, do we need to wait for a new board to arrive cause you have nothing to test it with?

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## printbus

What are you using to power the hub? Before hooking another RUMBA up to the hub, I'd use a multimeter to measure the voltage coming out of the hub power supply with it unplugged from the hub.  Maybe it's outputting more than it should when there aren't many things connected to the hub.  If you read more than say 5.25V, you're pressing your luck with anything connected to it, even if some devices seem to be able to handle it.

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## stridera

I actually checked that.  The hub is definitely at 5v.  I know it supports up to 3A, so I wondered if there was no current limiting features on the board so it was accepting the full 3amps and frying it.  Not sure.  Also, I plugged the hub in first and tried to plug in the board while it was powered on (for the first board.)  I think I saw a spark, as it touched the usb port.  Makes me think there is a power differential.  They're both plugged into the same place so there should be a common ground, but I'm not sure.  Before the second board, I tested everything I could.

Colin is letting me RMA this one last time and I'm afraid to plug it in.  (If I fry it again, it'll be a $80 fix each time.)

Do you guys have it plugged in via USB while the power jumper is on standalone?  I really don't want to make this a sddisk only printer.  :/  Maybe I'll grab one of my arduino unos and test each motor and switch.

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## Chadd

My power jumper is set to stand alone and I print via USB plugged straight into the PC. I sure wouldn't plug it back in through that hub again.




> I actually checked that.  The hub is definitely at 5v.  I know it supports up to 3A, so I wondered if there was no current limiting features on the board so it was accepting the full 3amps and frying it.  Not sure.  Also, I plugged the hub in first and tried to plug in the board while it was powered on (for the first board.)  I think I saw a spark, as it touched the usb port.  Makes me think there is a power differential.  They're both plugged into the same place so there should be a common ground, but I'm not sure.  Before the second board, I tested everything I could.
> 
> Colin is letting me RMA this one last time and I'm afraid to plug it in.  (If I fry it again, it'll be a $80 fix each time.)
> 
> Do you guys have it plugged in via USB while the power jumper is on standalone?  I really don't want to make this a sddisk only printer.  :/  Maybe I'll grab one of my arduino unos and test each motor and switch.

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## Draud

My board is in standalone and I can print via usb if I wanted to. It really sounds like the board doesn't like the powered usb hub.

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## tsteever

Can you take a picture of the board wiring? I'd like to take a look. I know that Colin confirmed everything is okay but a second set of eyes can't hurt. I had to switch my jumper over to load the firmware. Now it is in stand alone and I have always had a USB hooked up to either my computer or the Pi as I try to get octo print up and running nicely.

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## stridera

Sure, here are all the pics I sent Colin.  (Board is on it's way back right now.)  Images are too load to upload so I'll just provide links to them on my server.


http://www.stridera.com/wp-content/u...227_112417.jpg
http://www.stridera.com/wp-content/u...227_112453.jpg
http://www.stridera.com/wp-content/u...227_112517.jpg
http://www.stridera.com/wp-content/u...227_112538.jpg

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## tsteever

Your Bed relay is wired incorrectly. In the 4th pic down you have the two wires from your heated bed going into the bottom green disconnect. I am assuming then that the power from your power supply was hooked up the top two. As soon as you fire it up it will short out (I think). You need to have The red (+) from your power supply go into the top labeled IN and the negative (-) from your power supply go into the top of the bottom  green disconnect. You will then plug one of the two wires from your heated bed into the bottom spot in the top green disconnect (out). The remaining wire from your heated bed goes into the open spot in the bottom green disconnect. 


While I am not 100% sure that is the problem, it is *a* problem. It could be that when you fire up the board and that relay opens it shorts through the board and burns it up. I don't want to test mine to find out! Heres how i have mine...



Also, pull the empty pins out of the endstop plugs by pulling the tab up and letting the pin fall out. Not that it makes a difference but it can't hurt.

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## stridera

Oh, I know the bed was incorrect.  It wasn't actually wired up at all.  (No power going to it.  It was just both wires from the heater bed going into it, so when it was turned on nothing would have happened.)

I was well aware of that and told Colin such.

Also, this was the first board.

Second board I didn't have it hooked up at all.  It wasn't hooked up to the relay/bed at all.  Same thing happened.

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## BLKKROW

Have you resolved this? I recently order the 12" with Rumba so I want to make sure I don't fry my board.

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## sniffle

I think he's still waiting on another board.

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## stridera

I received my replacement board and I've been printing all weekend.  I'm afraid to hook it up to my computer though.  I did hook it up to my laptop (running on battery and not connected to the wall) and that worked.  I'm thinking of getting a raspberry pi and hooking it up to the same power rail as the printer and just controlling it using that.

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## BLKKROW

I am in no means an expert as I have not received my printer yet, but I did notice in the manual for Rumba it says to not use a USB hub. So that may be where the issue lies, like it was mentioned above.

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## stridera

Interesting.  I didn't see a manual for it.  (I just used the manual from makerfarm which never mentioned it.)  I guess it would have been wise to take a look first.  It's printing now, granted using memory card only.  But it works at least.

I think my raspberry pi idea will work as well and that will be enough for me.

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## BLKKROW

https://drive.google.com/a/overclock...ZWOXN1UVU/view

Starting on Page 61 it describes the Rumba board. It has a lot of info about updating firmware and such, this may help you in the future.

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## stridera

Oh wow.  That's new.  (The pdf file I have download only has 59 pages and ends at the endstop troubleshooting.)

Thanks for pointing this out.  I'll read through it now.

(Edit:  It was updated last week when I contacted him about it.  I'm guessing this was added due to my issue.   :Wink:

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## BLKKROW

> Oh wow.  That's new.  (The pdf file I have download only has 59 pages and ends at the endstop troubleshooting.)
> 
> Thanks for pointing this out.  I'll read through it now.


Its not a problem! Luckily I have been sick the last 4-5 days so I have been home from work and spent the entire time reading everything I could on the forum before I get my printer.

If you figure it out, please post on here  :Smile:

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## 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...

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## Mjolinor

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

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## 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.

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## 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.

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## stridera

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

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## BLKKROW

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


+1

I just hope you get it figured out.

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## 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.

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## 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.

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## 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.  :/

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## 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.

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## stridera

Oh, I see.  I thought that with my hub (since it's connected via a UPS.)

However, the raspberry pi and the printer were connected via the same power strip.  Thus, the line/neutral are connected and there shouldn't be a differential.  I'm not home, but I can check later, however, I can't see how it could be different.

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## Mjolinor

> Oh, I see.  I thought that with my hub (since it's connected via a UPS.)
> 
> However, the raspberry pi and the printer were connected via the same power strip.  Thus, the line/neutral are connected and there shouldn't be a differential.  I'm not home, but I can check later, however, I can't see how it could be different.


That doesn't matter. The output from the supply is naturally floating unless there is something preventing that like the negative from the DC connected to the ground. If you do not have that then potentially ground on the printer will be -6 (assuming a 12v dc) compared to ground on the PC.

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## BLKKROW

Have you double checked the jumpers on the board to make sure they are all in the correct positions?

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## stridera

Yeah, did that after the first board.  Everything works and I've been printing lots of fun stuff, but I'm still afraid to attach anything to it.  I bought this and hooked it up to my power rail, so with the shared ground I'm hoping it will prevent the next raspberry pi from shorting out... once it arrives.   http://www.amazon.com/gp/product/B00...?ie=UTF8&psc=1

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## stridera

So, the new Raspberry Pi shows up and now I get the following:



```
[  740.499047] usb 1-1.3: new full-speed USB device number 16 using dwc_otg
[  740.579015] usb 1-1.3: device descriptor read/64, error -32
[  740.769245] usb 1-1.3: device descriptor read/64, error -32
[  740.959289] usb 1-1.3: new full-speed USB device number 17 using dwc_otg
[  741.039028] usb 1-1.3: device descriptor read/64, error -32
[  741.229015] usb 1-1.3: device descriptor read/64, error -32
[  741.419004] usb 1-1.3: new full-speed USB device number 18 using dwc_otg
[  741.838948] usb 1-1.3: device not accepting address 18, error -32
[  741.919047] usb 1-1.3: new full-speed USB device number 19 using dwc_otg
[  742.339105] usb 1-1.3: device not accepting address 19, error -32
[  742.340747] usb 1-1-port3: unable to enumerate USB device
```

I guess it shorted out the usb chip or something on the board.  (I get the same thing from my Mac when I plug it [battery only])

I wanted the rumba so I could use the graphical display and multiple extruders, but now I'm not so sure it was a good idea.

This is very annoying...

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## Chadd

I don't think it is a rumba issue as there are many of us with the RUMBA running off USB with no issues. You for sure have another issue, no idea what it is but something odd is going on there.




> So, the new Raspberry Pi shows up and now I get the following:
> 
> 
> 
> ```
> [  740.499047] usb 1-1.3: new full-speed USB device number 16 using dwc_otg
> [  740.579015] usb 1-1.3: device descriptor read/64, error -32
> [  740.769245] usb 1-1.3: device descriptor read/64, error -32
> [  740.959289] usb 1-1.3: new full-speed USB device number 17 using dwc_otg
> ...

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## stridera

Perhaps.  I just wish I knew what other troubleshooting steps I could use to figure it out.  I have test equipment, but the Oscilloscope and multimeter both show normal readings.

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## Mjolinor

So you have measured between the case of the USB on both devices before they are connected together and it is 0 volts?

I don't mean close to 0 volts, even a very small voltage difference between them can pass  a huge current between the two devices.

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## stridera

Going from the ground of the usb port (basically the outside metal shell of the port) of both the rpi and the rumba board I get 0v.

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## stridera

Also, I just switched it to usb powered and tried to power the rumba board via the usb only (with the main power turned off) and it wouldn't even recognize the board or power it.

My guess is the usb blew out again.  Not sure what's wrong, but it's gone.

So this means I can't control it via the usb nor can I ever update the firmware on this (without removing the chip and using a programmer.)

I'm so confused.  Everything else works great.  It prints great from a memory stick.  But it's really hard to calibrate stuff when you have to create one-off gcode files to do random things.  *sigh*

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## Mjolinor

I missed a bit somewhere, I didn't realise you had plugged it in again.

You will get 0 now it has blown. It needed measuring before you plugged them together.

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## Mjolinor

From the schematic it seems fairly easy to forget the 16U2 USB <> serial and go in directly to the RX TX liines. I have done that on my Wanhao for the same reasons, the USB stopped working. I will replace the Atmega eventually but for now I just pick up the lines going to the main processor.

http://reprap.org/mediawiki/images/2...SCHEMATICS.png

From that picture all you need to do is get one of the USB serial thigns shown here:
http://www.geeetech.com/iduino-due-p...ter-p-655.html

The small board (DUE Pro USB/Serial), not the big one, they are usually on ebay but I can't find one right now.

Lift R17 and R18, solder a wire to one end of each of those resistors and solder the resistor back onto the side going to the main micro.

USB will then work again using the new USB<>serial adapter.

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## stridera

Nice.  I found this:  http://www.ebay.com/itm/Iduino-DUE-P...-/251753695359

Now, how to figure out which resistor on the board is r17/18.  (No silkscreening on it.)

I do see a COM header, as well as a JTAB, but no clue what that is.

I wonder if I can hook into either of those.

When I tested before it blew, I didn't get anything significant.  (Maybe 1-2microvolts, nothing more than I get when I wave the probes through the air.)

I also just ordered a couple more ATMEGA16U2-AU chips and I'll have to break out my reflow air solder unit to replace it.  Hopefully none of the caps/resistors are blown.

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## Mjolinor

I noticed that on the pictures. Buzz it out form pins 8 and 9 on the 16U2 and 3 and 2 on the 2560.

http://reprap.org/wiki/File:RRD-RUMBA_PCB.PNG

That has them marked so maybe your PCB does but you can see where they are easily enough, bottom left of the picture just to the right of the USB.

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## Mjolinor

You can hook into the COM header but you have to change the software to make it do that I think (not really sure) and as you can't change the software easily without a programmer it probably isn't worth the hastle.

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## stridera

I just noticed from the latest PCB layout that it is JTAG and not JTAB.  (heh)

I already have a programmer that I could probably just hook up.  That would let me reprogram it, but it probably wouldn't help me as far as controlling the printer from octoprint.

I did order the ATMEGA16U2-AU chip, so when that arrives I can try to replace it.  Not sure about the rest of the components though.

Thanks for all the help though.  It has given me ideas of how to move forward.  Not sure about the root cause, but maybe I can figure out how to get it up and going again w/o buying a new board.

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## Mjolinor

If you are using a Raspi to talk to it then you don't need the serial <> usb.

Use the serial port on the RASPI to connect to those two lines. Check the levels before you do, I am not sure if RUMBA serial lines are 5 volt tolerant or not.

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## tsteever

I have a Rumba and a Raspberry and no troubles. There has to be something that you are using that no one else is. My thoughts again return to your USB hub. I am not using a hub and have had no troubles. Are you still using that hub?

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## BLKKROW

Are you still using the USB Hub?

You may have an issue with your Motherboard or USB port if you are directly plugging it into your Mobo and not the Hub.

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## stridera

I haven't even got this one near my hub.  It's only been plugged into the raspberry pi which was plugged into the same power strip as the printer.

When I first plugged it in, Octoprint worked fine and I was able to control the printer.  I got it all setup, got the camera going and everything looked good.

I turned off my printer and turned it back on, which fried the usb port of the rumba and killed the pi.

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