UM S5 print head heatsink fan question

[bacon 0]

i am servicing a UM S5 3d printer for a client and the heatsink cooling fan does not turn on when printer is idling, nor does it turn on when the printer is heated up. i replaced the fan as it was completely gummed up with gunk and the new fan still does not spin during idle nor does it spin up during preheating.

[gr5 2,266]

oh that sucks.  Are you good with soldering surface mount?  I can post the schematic.  The controller is in the print head itself.  There's lots of great explanations out there with pictures of how to take it apart and get it together again.  I think it's a darlington transistor - I think maybe a 3 pin device if I remember right.  I'm guessing with the fan stuck for so many days/weeks/whatever that maybe the transistor blew.  This is not common on the S5 but was common on earlier printers like the UMO (ultimaker original).  I'll go find schematics and so on...

[gr5 2,266]

Here's the schematic and also the layout that shows the traces and the parts locations.  This is for the Ultimaker 3 but this board is basically identical to the S5 but the S5 board is about 10mm wider as the S5 has a wider print head because it has larger rods going through the head so you need to make room for that.

 

https://github.com/Ultimaker/Ultimaker3/tree/master/PCB files/2012-K Print head PCB

 

I think every part e.g. q1, q2, q3 is in the same location and serves the same purpose.  I've used the UM3 schematic to solder wires to the S5 board so I know they are very very similar.  Now that I think about it I probably do have an S5 schematic but I don't know where.

 

Instructions plus pictures and video for taking the S5 print head apart:

https://ultimakernasupport.zendesk.com/hc/en-us/articles/360039150672-Printhead

 

You can also choose to order just this circuit board.  Contact your reseller.  It looks like you are in Canada so the best place there is probably shop3d.ca - contact them to find the part number for the circuit board in the print head for the S5 and you can order it through them.  It may take a few weeks to get it though!

 

BY THE WAY - this fan only comes on when either core gets above 60C.  Did you heat the print core up before deciding it's broken?

 

[bacon 0]

thanks for the info! ill definitely take a look, and yes i fully heated the hotend and manually pushed some filament through it and the fan did not turn on

[gr5 2,266]

You could just short out that transistor.  I think that is what I would do.  Then the print head fan will just always be on whenever the power is on.  It is noisy so that would be a little annoying but it's a quick, cheap hack while you wait for a replacement board I suppose?

 

Just short TP1 to ground.  Or j1 pin 2 to ground.  Or short it at Q1 but leave base of q1 open.

 

I'm not saying the issue is 100% Q1.  It could be that D1 is shorted out as well.  But I'd say 90% chance it's either a broken wire or Q1.  Q1 takes the most abuse.  I guess I would test D1 as well to make sure it doesn't conduct when the red wire of the meter goes to 5V and the ground wire of the meter goes to TP1.  If that is not a complete open (same as air) then I'd remove D1 before shorting tp1 to ground (otherwise you have a short from 5V to ground and something may get destroyed).