Velleman Thermostat Not Working

[mtcorby]

Hi, I have assembled the SeeMeCNC H-1 with the stock electronics, changing the R5 resistor in the thermostat as specified. I have been able to use Linux CNC to get the stepper motors working, but the thermostat does will not give current to the heating resistors. I checked the power input, it is getting 12V. I checked the resistance across the thermistor - it is about 1M ohm when unplugged, and about 130K ohm when plugged into the thermostat. The red LED for "Relay On" is lit, but there is no power to the heating resistors. I move the knob, but to not hear a click. I hear a click when I first plug in the H-1, but I'm not sure if it's from the thermostat or something else.

Anybody have any ideas? I've double-checked that the polarities are correct on all the polar components, how can I trouble-shoot from here?

[midget214]

Hi,

Well it might be 1 of 2 things

1. Your heating resistors' wires are touching the metal part of the hot end, causing it to short.
2. You might have defective resistors.

Other than that I am not sure what it could be

[mtcorby]

Possibly another clue. Just checked the resistance of the resistors. Together they are 3.6 ohm, which seems right, because that gives I = V/R = 12/3.6 = 3.3A, which seems like a good amount of current to do some heating. So I put a jumper between the two thermistor leads, which turned off the relay. It then read 12V going to the resistors, but after 3 minutes I still felt no heat on the extruder tip.

[tom10122]

Sounds like the heating resistors are wired wrong, http://seemecnc.org/assembly/H-1-Basic- ... acking.jpg its a little old but the velleman wiring is the same

[mtcorby]

narrowed the problem down to the relay on the thermostat not working properly. didn't want to wait to order another one so I grabbed one from radioshack, even though it didn't fit on the PCB. I simply screwed on an extension board to the thermostat, and ran wires from the extension to the proper locations. thermostat is working fine now. I have Linux CNC and Slic3r 99% set up (3 axes work but not the extruder). I used the EMC2 config provided here, but converted units to inches (I'm an American mechanical engineer so that's the only units I ever use).

[wildideas1]

well of all things that have been going wrong with setting up the heat bed and trouble shooting with everyone's help here on the forum, turns out that My relay was bad and causing the weird shorting issues. Ordered new velleman today from seeme and will get new relay from elec shop as soon as i can get their, but once again waiting patiently to rock on.