Apr 12

2nd thermistor at -15c?


Edited: Apr 13

Update: Looks like dodgy thermistors, something wrong with the connection at the black shrink wrap near the head end.


Now that the guides/firmware are up for this I've given a bash at getting it going, but after going through the firmware install/setup the 2nd hothead is allegedly at -15 degrees on the touchscreen.



- Re-uploaded the Proforge 2s Dual firmware with fresh download

- Verified I chose the Mega2560 board/CPU

- Tested both thermistors which at the time both read 130.2kohm IIRC

- Reseated the thermistor connections


I've checked in the serial console and it sees the -15c too, so it's not a arduino -> lcd issue.


echo:Marlin 1.1.9


echo: Last Updated: 2018-08-01 | Author: (Makertech 3D)

echo:Compiled: Apr 12 2019

echo: Free Memory: 5185 PlannerBufferBytes: 1232

echo:Hardcoded Default Settings Loaded

echo: G21 ; (mm)


echo:Filament settings: Disabled

echo: M200 D1.75

echo: M200 T1 D1.75

echo: M200 D0

echo:Steps per unit:

echo: M92 X80.00 Y80.00 Z400.00 E98.00

echo:Maximum feedrates (units/s):

echo: M203 X300.00 Y300.00 Z5.00 E50.00

echo:Maximum Acceleration (units/s2):

echo: M201 X1000 Y2000 Z100 E10000

echo:Acceleration (units/s2): P<print_accel> R<retract_accel> T<travel_accel>

echo: M204 P2000.00 R5000.00 T2000.00

echo:Advanced: Q<min_segment_time_us> S<min_feedrate> T<min_travel_feedrate> X<max_x_jerk> Y<max_y_jerk> Z<max_z_jerk> E<max_e_jerk>

echo: M205 Q20000 S0.00 T0.00 X3.00 Y3.00 Z0.30 E10.00

echo:Home offset:

echo: M206 X0.00 Y0.00 Z0.00

echo:Hotend offsets:

echo: M218 T1 X0.00 Y-19.00 Z0.00

echo:Auto Bed Leveling:

echo: M420 S0 Z0.00

echo:PID settings:

echo: M301 P18.48 I1.13 D75.30

echo:Z-Probe Offset (mm):

echo: M851 Z-3.00

ok T:22.97 /0.00 B:22.50 /0.00 T0:22.97 /0.00 T1:-15.00 /0.00 @:0 B@:0 @0:0 @1:0


I've had a look in Configuration.h and it all looks good so I'm somewhat stumped.


Any ideas?

Apr 13

After performing the dual head upgrade, temperature on both of my print head thermostats are now randomly jumping around from -1 to 34 while the system is sitting idle

Apr 13

Interesting after powering on my Proforge 2S this morning I noticed my hotend temperatures are doing weird things like @_aaron has. The first temp is changing between 19-25 quite regularly, and second flips between -15 and 230-280 degrees (the hot ends are still not on of course).

Apr 14

Likely a sign of a bad/shorting thermistor. Check wiring first, but you may need a replacement.

May 10

I also have this negative reading from time to time... there must be a software problem I think 🤔.

May 10

Or maybe electrical noise

New Posts