Mega 2560 Keeps burning out. I have burnt two out.

Hi guys. My first post here of hopefully many. I have been building or at least trying to build a Kossel mini. This is the first printer I have built and to be honest I am a bit of a noob when it comes to the electronics. Anyway, I have burnt out two generic Mega2560s , this is really frustrating because it is the only part I have left to do before I can print (not to mention costly) :'(.

Anyway I plan on ordereing 2 more (just to be safe), but there has got to be something I am doing wrong which is burning out the Megas which I dont know why. I have tried running both of the audrinos without the ramps connected and the computer will not detect them at all, they still both light up.

I noticed a smell coming from the second mega so I turned it off straight away once I noticed it, but it was too late the same thing.

Here is a picture of my Ramps board, I feel as though it might have something to do with how my power supply is connected to it. The power supply is a Thermaltake 420W (so its not too bad, but it is a still a generic ATX PSU).



If anybody has any suggestions I would really appreciate it, because I am really lost and fed up .

Edited 1 time(s). Last edit at 03/17/2014 06:57AM by nicayd.

Post a picture of your Mega..

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Waitaki 3D Printer

Here is a picture of both of my megas

Don't plug your ramps in again until you've checked I think you have the drivers in backwards not familiar with those particular drivers. Which means all of the drivers are definitely bad if they're plugged in backwards and possibly the ramps board. Find more literature on wiring the ramps[www.youtube.com]

The pots on the stepper motor drivers are normally facing the other way (assuming what you have is a pololu clone). Double check you have them installed correctly

Hi
I had the exact same issue, i went through 3 mega's before i found the issue, in my case it was a dodgy ramps, for some reason the ramps kept blowing the 5V regulator on the mega (i think one of you're pictures shows a lump on the regulator). I purchased a new ramps and touch wood havent had an issue since. You can stop the ramps feeding power into the mega by removing the D1 diode (assuming its a ramps 1.4) from the ramps and powering the mega via the usb

Quote
eci22
The pots on the stepper motor drivers are normally facing the other way (assuming what you have is a pololu clone). Double check you have them installed correctly

I agree I'm surprised other people haven't looked at the picture it looks to me that they are in backwards in which case they are definitely burned out and possibly the ramps look at the youtube link I posted earlier

drivers look like their install right [www.pololu.com] at least the ground in the right place

Looks like the voltage regulator on the mega, I had this happen as well, I replaced the regulator with a beefier one and haven't had an issue since.

Is D1 (diode 1) present on your Ramps board? I believe you said ATX supply, you are only supplying 12v correct?

Those are DRV8825 step drivers, they are supposed to be in that orientation. A4998 have the pot facing the other side.

You must have a short on the ramps. or maybe a really bad driver... (alot of ppl had drivers already broken on arrival).

I have those exact drivers on my ramp board.

Edited 1 time(s). Last edit at 03/17/2014 04:19PM by Rigor_M.

Also,

Looking at your first picture, looks like the extruder driver has his heatsink on the the pins.. I would look at that one first.

If you want a good trick to install heatsinks: put some kapton tape under the heatsink, cut to size then super glue the heatsink on the chip. Make sure that it ONLY touch the chip and nothing else around.

Edited 1 time(s). Last edit at 03/17/2014 04:18PM by Rigor_M.

Thanks for the help guys . I havent had a chance to look at my ramps board yet this morning but will take another look when i get home.

With the heatsinks I had those applied with thermal paste they definitely wernt touching anything else. Everything else seemed to be working fine before the second board burnt out.

When putting power to the board from the 12v plug from my PSU should I be plugging it into the 5 and 12 amp plugs on my ramps. The reason i ask is because when i first got it all working I found that the steppers wernt working at all i then proceeded to put power in to those two power inputs (same as in the picture) and turned the drivers around and it seemed that everything worked briefly then it burnt out fairly quickly. I am wondering if it could be that im putting too much power into the ramps. Anyway do you guys think it would be advisable to purchase a set of ramps and audrino and maybe drivers as a kit from the same person? Because i previously just bought cheapest i could find.

If you had the drivers in backwards even for a split second they are definitely no good and possibly the ramps board is bad also like I said I'm not familiar with these drivers but if there right now and you had them wrong and powered it up they are definitely no good

Thermal paste is not a type of glue. its a heat transfer paste.. they could of moved.

Are you using a non electrically conductive thermal paste.

The non-conductive thermal grease types includes silicone and zinc thermal greases.

The conductive types includes silver, copper, and aluminum-based greases.
These are considered superior, but must be used carefully or they can cause electrical shorts
if applied to the microprocessor's pin s or the electrical pathways on the circuit board.
[whatis.techtarget.com]