Building a Prusa Mendel. Using the hot end from Adrians universal mini extruder: Universal mini extruder the thermistor is the more robust one, referred to at the bottom Thermistor I have updated the firmware table with the data provided for that resistor. When I use 'check temp;' in pronterface I get ok T:0 B:0 In pronterface I set heater to 185 (for PLA) I waited 5 minutes for the heater to warm up On the resistor theres 131k ohms resistance at the ramps board end. Have checked for shorts on the thermistor & the power resistor against the brass heater block. I test by holding (in pliers) a piece of heatshrink against the hot end brass block , but no heat Any ideas why the heater is not heating? Thanks in advance. Mike Update : Solved: there's no resistance in the power resistor at the board end. Probably a break in the bootlace ferrules. https://reprap.org/forum/read.php?1,111848,111848#msg-111848 Thu, 15 Oct 2026 22:49:14 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?1,111848,111848#msg-111848 https://reprap.org/forum/read.php?1,111848,111848#msg-111848
Using the hot end from Adrians universal mini extruder:

Universal mini extruder

the thermistor is the more robust one, referred to at the bottom
Thermistor

I have updated the firmware table with the data provided for that resistor.

When I use 'check temp;' in pronterface I get ok T:0 B:0
In pronterface I set heater to 185 (for PLA)
I waited 5 minutes for the heater to warm up

On the resistor theres 131k ohms resistance at the ramps board end.

Have checked for shorts on the thermistor & the power resistor against the brass heater block.

I test by holding (in pliers) a piece of heatshrink against the hot end brass block , but no heat

Any ideas why the heater is not heating?

Thanks in advance.

Mike

Update : Solved: there's no resistance in the power resistor at the board end. Probably a break in the bootlace ferrules.]]> Anonymous User General Sun, 01 Jan 2012 12:24:13 -0500