MakerGear Forum

Hello, we're having an odd issue with our M2's fans. The printer is the 12v/19v version, has 3 12v fans (2x40mm, 1x50mm). The 50mm fan controlled with M106 (plugged into Extruder Fan 0) works fine. I can control that, turn it on/off, change speeds, etc. The 40mm fans (plugged into extruder fan 1) are running near full speed all the time. A few weeks ago, I was able to control it with M108 just fine, and it ran at S155 as it should. One night, I noticed that they seemed louder. Normally, when I would turn the machine on (or connect to it via pronterface) the fans would kick on, turn off for like 1/4 of a second, then kick back on and run at the 155 speed and I could control it with M108 Sxxx if I wanted. This time, I noticed it was louder. I tried to control the fan speeds and I could adjust it from somewhere around S100-S255 but no lower. Nothing was changed on the printer that I am aware of, no firmware changes or anything. In an effort to troubleshoot the issue, I tried to hook up a multimeter to test the voltage and compare the FAN0 to FAN1 plugs because although FAN1 was having issues, FAN0 still worked normally. I hooked up my multimeter and for some reason the two terminals on FAN1 shorted out and blew the 5amp fuse so no fans would work and the extruder wouldn't heat.. Determined my multimeter is faulty, it wouldn't test anything else properly and the wires seem a bit iffy now.

I ordered a new fuse, replaced it and it turns on again and works, but now I can't get M108 to do anything. The two 40mm fans stay at or close to 100% and the extruder can't keep up in temp (v3b). If I angle the fan away from the extruder it helps, but obviously this isn't the best solution. Turning on/off the printer now the fans just turn on to 100% instantly and stay there instead of powering on, turning off, then powering back on like they used to. I tried to re-flash the firmware at one point just before the fuse blew, and have tried flashing a few different variations I've found that are for my model, and nothing seems to make the M108 command work or the 40mm fans function properly.

Anyone have any suggestions what I should do next? Should the M107 command stop the M108 fan since I'm not sure if it actually realizes it's a regular fan like the 50mm.


Thanks,

Bill

Bill,

You sure you have them in the right input's on the rambo board?

well multimeters dont usually like to read pwm voltage very well or accurately. some do most dont. its sounds to me like the mosfet controlling the fan power is stuck in the on position. i am only slightly handy with electronics. far from a pro so someone else can give their input. if that the case and the mosfet is stuck then your only option i think is to replace the rambo.

Contact Ultimachine and see if you can purchase a discounted RAMBO, I think you blew the channel out like jimc said. Ultimachine has worked with me in the past before, they're great about it.

(MG may also step in here, but you're waaay outside their warranty if you have a dual-supply machine ... although maybe you can weasel the polyfuse replacement RAMBO now?)