Happy to have found this thread. My biggest problem is bed wiring. But first…
I too run a 4 Mini “Farm” with heavy usage. Each printer runs 12 to 22 hours per day. 3 PLA and 1 ABS. All were bought used. Serial number range from 1100 to 10500.
Generally satisfied with the Mini. I did buy 4 of them. Will probably buy more 1.03s or 1.04s and do the preventative upgrades. Not a fan of the Z-Belt design.
Now for my rant…
ALL HAVE BED WIRE FAILURES. On the 1.00 to 1.03 version units all wires have been removed from cable chain and long loops have been spliced in. So far so good. On the 1.04 only the probing ground wire is suspect so far.
Wires are cracking because the curve of the lower (bed) cable chain is too tight. Wires twist too much and crack inside the insulation.
Should have been fixed (re-designed) long before now. Wires should have a larger radius turn. Lulzbot solution is to fatten up the insulation to smooth the bending. Delays the failure. Is NOT a fix.
First clue was “Thermal Runaway” shutdown. Thermistor wires break and temperature reading drops suddenly. Firmware calls it runaway aborts the print and shuts off the power. VERY THANKFUL for that safety feature.
2nd was the bed wires themselves. Bed would not heat.
3rd was the Y endstop wires. During Z-probe belt would skip because limit switch wires were broken.