Simple Metal Died During Print

[craigj]

My simple metal died in the middle of a print the other day.
I came in to find it stopped in the middle of the print
I thought - well, maybe I had a short power failure?
so, I scraped off the half print and tried to start the job anew.

I use an LCD panel to print from SD Cards
when I tried to restart my print job the LCD screen flickered and reset to the Info Screen
I did this several times, resetting the power each time and got the same results
Then I tried to just heat the extruder so that I could remove the filament.
I got the same flicker and reset to the Info Screen when I depressed the knob to select the temp.
I am also seeing this behavior when I attempt to heat the bed via the LCD

If I attempt to move any of the axis, or perform an auto home, the bot starts to move sluggishly then stops after a cm or two and the motor makes somewhat of a grinding noise (stalling?)

I checked all of the connections under the bot and everything appears to be in place.
I am not sure how to troubleshoot this from this point
I am looking for any suggestions on my next step for troubleshooting this issue

[cbxbiker61]

If you can swap out the power supply that'd probably be the easiest/first thing to do. If you can't swap power supplies, try to get a volt meter connected to the input leads and see if you have a nice solid ~12V.

[craigj]

While disconnecting my power supply I discovered this!
All 3 ground wires are charred and have disconnected themselves from the connector on the PSU lead.
* they were still in the sockets and touching the pins when i found this which explains why the bot would power on but would give up on any operation that required substantial power.

I am sure that I can cut back the wires and repair this connector
But then what?! Can I trust that if I do this bot will not burn down my house during the next print!?

Beyond repairing this connector what should I do to ensure that my bot is safe to run?

20180419_014224.jpg

[cbxbiker61]

That 6 pin connector should be able to handle the current draw of a properly functioning printer. The 6 pin connector is good for 360 watts.

There are two things I would be thinking about here.
1. The connector had crap connections to start with, doing a proper repair job would fix this problem

2. Something like your heater bed has a short which is causing too much current draw, you would have to carefully inspect the way that the heater is mounted and make sure you don't have any shorts, also test the resistance across you heated bed terminals to make sure it is not too low.

Plug 12V and your resistance into this calculator to ensure you are not sucking too many watts.
https://www.rapidtables.com/calc/electr ... lator.html

[craigj]

I disconnected the bed from the terminal on the printrboard.
from there I measured 1 ohm across the ends of the line to the bed

The calculator shows that for 12v this is 144Watts or 12 amps.
so I should be ok, right?

[cbxbiker61]

You should be fine at 1 ohm.