Left fan not working on UM2 - Resolved!

[nelson-silva 0]

Hi,

 

We just set up our new UM2 printer here at our office and just started the UM Robot test print, however we noticed that the left fan (when you look at the printer from the front) is not working. Is that normal ? Both the right and back fans seem to be working properly.

We noticed this because the nozzle movement made the robot's right hand support move around so we're guessing it's because the material did not cool down as it was supposed to.

 

[ian 32]

the back fan is meant to be always on.. and when printing the two fans.. left and right should also be on.

Check your cable connections going to the base of the left fan.. also if this looks all ok... you can carefully remove the shield around the electronics and check the connection there also... check also that the cable wire going the left fan has not been pinched or cut behind the print head..

Keep us updated.

Ian :-)

 

[IRobertI 520]

Just to add to Ian's post, the side fans don't come on at the very start of the print if you're using cura's defaults. They will come on gradually during the first few layers. You can however test them manually if you go into the tuning menu after you have started the print.

Also, check to make sure that the little pins inside the fan connectors are secure. On one of mine the pin was loose and I had to re-secure it in place by bending out the little "hook" that locks it in place before stuffing it back into the connector.

 

[nelson-silva 0]

Ok, we just switched the connectors (above the extrusion head). The side fans seem to be connected with green-green and yellow-green wires. After switching the connectors of the left and right fan we now have the left fan working but not the right fan so at least we now know that both fans are working... they only work when connected to the yellow-green connector so there seems to be a problem with the green-green connector any ideas of what might be the problem ?

Robert: We're using the UM robot and the fans start right after the first layer. Also, i did not find an option to turn on the fans in the tuning menu, i can only control the speed.

Thank you all for the support! We're looking forward to having this sorted out so we can start doing some cool prints

 

[gr5 2,178]

Also, i did not find an option to turn on the fans in the tuning menu, i can only control the speed.

 

When speed is 0 they are off. When speed gets above around 30% they start spinning. Between around 10 and 30 percent they need a little push to get going.

 

e just switched the connectors (above the extrusion head). The side fans seem to be connected with green-green and yellow-green wires. After switching the connectors of the left and right fan we now have the left fan working but not the right fan

 

This is bizarre since they are wired in series. "wired in series" is the same way dual battery flashlights work. If you remove one battery, the circuit is open and the light will not come on. So if you disconnect either fan, both should stop.

The obvious conclusion - the only thing I can think of - is that the green-green wires are shorted together. Maybe inside the connector? Or maybe it's just totally wired up wrong. Could you photograph the wiring please? Include the wire that connects the two connectors together.

 

[gr5 2,178]

I just had another thought. Illuminarti mentioned that when he wired up a fan backwards it didn't work (didn't spin). Normally when you wire a dc motor up backwards it spins the other way but not these fans.

My theory is that the "green green" connector is wired up backwards so the fan connected there gets power but won't spin.

 

[gr5 2,178]

If it's wired up backwards then you can tell because the "loop wire" in my drawing below should normally connect a black wire on one fan to a red on the other but if it's wired wrong it will connect a black to a black or a red to a red:

 

[nelson-silva 0]

m/ It's working properly now.

The loop wire was connecting two black wires so i just switched the green-green connector wires and now all the fans work as expected.

Glad to be part of the UM user community. Fantastic support!

Thanks.