Frozen Prusa Mid-print

I am having huge issues with my printer freezing mid print.. Often, it will freeze towards the beginning of the print and all movements are locked unless I unplug the printer from my computer for a few second. The hot end also retains the heat while frozen. It is almost like it just locks up. I have also successfully printed 3 hour prints before and other times I can not complete 2 minutes worth of printing! Here is my set up and what I have tried so far..

-Prusa
-printrboard
-pronterface
-slic3r
-115200 baud rate
-Macbook pro with os x 10.8.4
-run with computer power plugged in
-set sleep for hard disk and computer to never

and here is what I have tried..

-ferrite chokes on usb cord
-changing baud rate to 250000
and other suggestions I have seen online..

Please let me know any suggestions that you have as I want to get my printer running!
I do not have access to a sd card but I might have to purchase one in order to solve this problem..

Thanks,
Clayton

I found that switching some appliances on and off near the printer can do that. I also had a bad batch of USB cables, they would break connection at the slightest movement. Replaced them and had no further problem.
I also had a Printrboard that had a bad connection on the USB port, the very small wire connections would disconnect at times. I had it replaced with another one that I noticed had been secured with epoxy adhesive around the USB connector, so that showed me that they were aware of this problem and found a way to solve it.

I've had this happen before. Low-quality power supplies can be very sensitive to voltage spikes; cheapo PC PSUs in particular will often sputter enough to kill your print if you run a vacuum or microwave or something on the same circuit without. Paper shredders, too. Don't ask how I know that one...

You can tell it's deeper than a firmware issue since all modern firmwares will shut off the hot end if, say, the thermistor connection comes loose (another common cause of mid-print halts).

I had paper shredder issues, as well as seemingly random stops. I've heard conflicting reports about voltage spikes or USB interference being the cause. However, the people suggesting USB interference seem to be correct in my case, since their advice fixed the problem.

When I switched from a 6ft USB cable with a ferrite choke to a 3ft USB cable with a ferrite choke, the problem completely disappeared. I can now shred 2D and print 3D simultaneously. #lifehacking

Karmavore Wrote:
-------------------------------------------------------
> When I switched from a 6ft USB cable with a
> ferrite choke to a 3ft USB cable with a ferrite
> choke, the problem completely disappeared. I can
> now shred 2D and print 3D simultaneously.
> #lifehacking


Ahh but can you shred your failed 3D prints?

I have a printrbot simple with the same problem, its caused in my case by temperature sensativity on the board, if you squirt the board with a blast of cold air it will just startup again mid print and carry on, because the hot end is still hot, it will continue from where it left off.

However dont leave it for too long in that state, if the heat is on, and its not reading the thermistor, it will be winding up the temperature on your hotend.

I thought it was a usb comms problem at first, but it does the same from an SD card print, you may also notice that it starts to slow down before it stops. Its very strange, its like the battery running down on a toy.

I think the ceramic resonator used on the board is temperature sensative. Resulting in my case with the mpu clock stopping completly once the temperature gets above 30 degrees.

I had a desk fan blasting cold air over the board and it stabilised again, but not a good long term solution.

A cheap ups with spike protection or a line conditioner would solve the power issues. Also watch what cords your usb cable is near some will bleed interference into it.

It is a possibility that it is an electrical connection issue to the heaters. The heater is the only part allowed to keep working if there is an error that would safely stop your print.

If anything go over your wiring, and retape the thermister in place, and assure it is not shorting out or disconnecting.

With motors disabled lift z axis about 60mm, and move xcarriage by hand all the way to the left and right of carriage as fast as you can safely. Do this at least 20 times and see if thermister value changes dramatically during this time (like more than 20deg). If it does then you have a wiring issue. Otherwise it may just be best to replace the thermister anyways.

Other conditions that would cause line error during communications are likely recoverable.

In my humble option. Others may chime in with more details or other solutions.