Velleman mk138 noisy and maybe interfering with extruder

[gijed]

So I have a velleman mk138 for the hot end and it's kinda noisy in that the relay is being switched on and off absurdly fast. I don't think this is normal but maybe you guys have a better idea about this. That aside, the mk138 is (I think) interfering with the Easydriver or the wire between the Easydriver and the 3axis board. What's happening is the extruder is jittering violently when the mk138 is running. The hot end does get to the right temperature and the extruder does extrude, but I cant control the extruder now.

What do you guys think?
Do I need to shield the step and dir wires?

[mhackney]

Did you gang the 12 volt and ground wires from your power supply as shown in the H-1 Electronics Manual? You may not be getting enough current from the supply to the devices. I would start there and make sure you have suitable gauge wire.

Michael

[gijed]

Spot on, mate.

[mhackney]

Does that mean my debugging actually worked and you solved the problem?

Cheers,
Michael

[gijed]

haha, yes and no. It was working just fine for about 30 seconds then something clicked and it went crazy again.

[Leeway]

I'll say that this type of rapid relay oscillation is what happened to one of my MK137's just before it quit working. Both quit working after a few hours of work. I haven't yet tried to fix them, but it is likely a diode.

Shielded wire is always a good idea from the start, but not all my machines use it.
Proper grounding helps to eliminate noise. Sometimes simply twisting wire sets can help. That and re positioning boards. Electrical noise will drive you crazy sometimes to troubleshoot if that is what is really happening. Like a leak in a roof, it could be coming from just about anywhere.

[gijed]

It turns out that the connection to the thermistor was damaged. Now the mk137 is working great, however my extruder is still going crazy. It's not violently jittering any more, now it's moving smoothly on its own, usually in sync with another axis moving. It's disappointing because if i could control the extruder then i could finally get something printed.

[johnoly99]

So your extruder only moves when another axis does? Can you try jogging it with the +- keys on your keyboard? If it mooves smoothly but only when another axis does, id say you have the step pins either set up wrong in mach, or the board. Maybe pist a pic of your wiring setup, and a screenshot of your pirts and pins mach screen