I was plagued with stops for 6 months - finally fixed once and for all last week! So pleased. There are a dozen, probably more threads discussing it, but I think a lot of the time it is a noisy supply, which can be a bad ferrite installation, or noise on the USB connection. I finally solved this as follows, a bit of effort, but having had stops between once every 10mins to killing a job after 5 hours for the entire time I owned the printer, I can now run 40 hour jobs without any issue - literally zero stops since the following:
My theory was that it was the USB signal getting interference after making sure the power was clean. I checked the power making sure they were unlikely by using a bench supply (lab equipment) AND testing it on the board using a scope. Also many things about the way it would stop seemed to imply it was communications, not least the fact that loads of printers based on USB-Serial comms to a arduino have this issue, hence the Repetier firmware with it’s error correction stuff. Loads of stuff about that on other forums for other arduino printers / CNC machines - seems the usb really has to be clean of interference to stand any chance and in a bedroom surrounded by PCs, a massive radiator behind it hooked to a noisy domestic earth, a set of flurescent lights and their starters in the kitchen beneath (complete with microwave) I really was facing an uphill struggle!
So I figured on eliminating EF interference on the USB cable and in order to do this I needed a short as one as possible to stop it acting like an aerial. I had tried the much suggested powered hub idea to some avail but still not perfect - but the fact that it reduced the frequency of errors a bit made me think I was onto the right thing. But how to get a very short USB cable to a computer? NEW - VERY SMALL computer! I tried getting the thin debian build of linux on a Raspberry Pi to play ball with Mono and Repetier, and then a load of other gcode spoolers, but none were any good, so instead, needing a very small computer… bought a little ‘New Unit of Computing Intel’ box, a little 10cmx10cmx3cm box with an i5 + tiny 64GB SSD disk and 8GB of RAM, very cheap and runs very well. Installed Win7. Then ran a 15cm USB cable (amazon) to the controller, but not before adding shielding to said cable: silver foil coiled round + insulating tape + silver foil crunched round + insulating tape + steel braid + plastic coduit + insulating tape. (not kidding - look how chunky it is in the pic!)
But how to mount the miniature PC so close and avoid all the noise generated by said PC killing the board directly? Answer, house the entire controller board in a similarly insane Faraday cage made of all the amazon boxes from all the things bought recently with layers of alu foil inside, doubled all those up, then formed them into a sort of tunnel. Tunnel you ask? Well all that insulation would fry all the FETs in minutes, so I thought I better add some not so passive cooling and so needed to make my cage a funnel, 10cmx10cm at one end for a big PC case fan running off the 15V supply, then 5 layers of staggered chicken fencing (read, 5mmx5mm galvinised steel mesh) with several disks of alu foil over the motor area all to stop noise from the fan - even though it was an inducting job - no brushes - I still reconed on some fields from the switching, that lot attached to the wide end of the funnel shaped tunnel, and open at the top end, so no chance of over-heating either!!
Basically, an insanely over the top and ugly effort, lots of tape but works!! Oh and the minicomputer is good enough to run prints while streaming a webcam to the internet so that I can watch prints while at work and I can RDP into the PC to control things and stop it if it is going badly for whatever reason. All made either with fiber internet which has just got to my villeage, only 10Mb upload compared to the 80 down, but 10 will def do and cant complain for $30/m. That allows for 720p on one of my monitors at work watching the print. Although its a bit confusing as I have a mirror on the bed.
I have lots of other mods, but that one is probably the only unique one. Other peeps have mirrors and cunning fans like mine. I guess my mirror is cool in that I got a 218x218mm one cut to fit so that I could maximise the bed size and it is now more level than a level thing so getting that mirror like perfect first layer which is nice.
odd, that pic wont work. well the url is: postimg.org/image/h78ww5swz
Now to work out how to attach a picture…