MINTEMP and poor quality wire  

MINTEMP and poor quality wire

Documenting the THIRD failure (1 print fan and 2 hotend thermistors) of my Prusa i3Mk3 here: Another MINTEMP message and 0/0 being displayed for the extruder temperature. This will be the second hot end thermistor failure for my machine in 5 months of casual use.

After installing the replacement supplied by Customer Support, I decided to see why the thermistor had failed. Found an open connection in one of the conductors between the plug and the thermistor itself. I narrowed the location of the break in the wire, carefully cut open the insulation and THIS is what I found:

I know its hard to believe - but what you're looking at here is a 100% complete internal discontinuity inside the insulation in a manufactured appliance wire. This is complete JUNK. This break point is located approximately 1/2 way between the plug and thermistor - right in the middle of the wire run where everything is neatly wrapped inside the spiral wrap. The wire was in no way abused, kinked, crushed or cut.

Here is the wire manufacturer:

"Dianhang" (SUZHOU DIAN HANG ELECTRONIC CO LTD) is the manufacturer. This is simply a piece of JUNK wire made in a crap factory in China.

This is also the SECOND wire failure on my Mk3. The first one was when my print fan quit working - and again I found an internal break in the wire. Fixed that one myself, but it cost me several hours to do so, and makes Prusa look bad.

PRUSA - please discontinue using wire from Suzhou Dian Hang Electronic Co. The wires connecting the moving print head to the Einsy board get lots of movement. They should be of very high quality, probably need to look at sources from Europe, Japan, or the USA. This Chinese stuff isn't a good idea.