print head fan broke down

[tjunyuan 0]

Hi, happy new year to you guys.

I have a ultimaker which shipped in september. I have noticed that the fan at the extruder head will work only intermediately when i was starting out on the machine. sometimes the fan spins, sometimes it does not. Now recently (in the month of december), the fan stopped working completely. Someone mentioned that it could be a electrical wiring problem. I have rewired and adjusted and jiggled the various wires, paying attention in particular to the one connecting the fan to the circuit board. But nothing seems to be working this time round. Anyone knows what could be the cause?

i must say that it is quite disappointing to have something break down barely 6 months into owning it. i appreciate it if anyone is able to offer some assistance to fixing it up again.

[joergen 2]

There is a BD679 darlington transistor driving the fan on the UM board. Since you checked all the wiring, I would check if the transistor has dry solder spots (resoldering fixes this, as this occasionally can happen in PCB production), or it might have died (unlikely, but I killed mine when I did something wrong with a different (3 wire) fan, and had to replace it)

[tjunyuan 0]

Hi, thanks for replying.

Can you provide an image of the location of the transistor. I'm not too familiar with the electrical workings of it.

[Daid 306]

The BD679 is located below the extruder fan connection. It's the black thing next to the step motor driver:

http://www.reprap.org/mediawiki/images/ ... totype.JPG

You could also test if the cable is bad by plugging the fan into the board directly, without using the 2meter cable. And finally you could check the fan by connecting the fan to the "always on" fan connection used to cool the motor drivers.

[tjunyuan 0]

Is the darlington transistor that you were talking about circled in orange in the following image?

Ultimaker_Original__Press_Kit.zip

I noticed that there is a gap in the soldering for the transistor. I just want to confirm if that is the cause of the problem. Since i am a newbie in these matters of soldering, i don't want to mess up the PCB.

Ultimaker 2 Press Kit.zip

[ddurant 0]

Is the darlington transistor ...

I have no clue..

 

I noticed that there is a gap in the soldering for the transistor. I just want to confirm if that is the cause of the problem. Since i am a newbie in these matters of soldering, i don't want to mess up the PCB.

...but I'd definitely redo that joint!

It's probably worth going over the whole board and touching up anything else you find too, while you're in there. As long as you're careful (and, of course, don't have it plugged in!) I don't think there's much risk of messing up the shield..

[joergen 2]

Absolutely correct, that darlington bd979 needs resoldering, and Dave is correct, resolder everything else that looks suspicious. While you resolver it, push it down a bit more, or carefully bend it towards the PCB. It looks like the wood above pushed a bit too hard down on the transistor, as if there wasn't enough clearance...

[tjunyuan 0]

hmm i think you are right about the wood covering exerting too much force. because when i tried connecting with the wooden cover off, everything worked fine. with the cover on, the fan stopped working again.