fan printhead don't work anymore

[roald 2]

hello, the fan printhead from my original ultimaker wont work anymore?

when i connect my printer with the powercord and usbcable en put the power on

i have a voltage of 19V on the purple and blue wire on top of the printhead. and when i start printing the voltage drops to 14V but the fan wont start to drive anymore??

when i test the fan on a 12v battery it works.

anyone a idea what is wrong?

Roald

 

[gr5 2,173]

Maybe when you put 12V on the wires you fixed something? Loose wire?

 

[roald 2]

Maybe when you put 12V on the wires you fixed something? Loose wire?

 

you mean there is maybe a cable break or a not good connected wire?

 

[gr5 2,173]

Yes. When you put the 12V on the fan, was it still attached to the print head? Or did you remove it? Did you apply 12V at the print head or underneath the UM?

 

[roald 2]

 

[gr5 2,173]

Ah. Good picture. Okay. This implies the darlington transistor is blown.

Q4. It has enough power to drive the multimeter to 17V but not enough power to drive the fan. You attached 12V to the wire under the printer right?

This transistor is easily damaged by normal use. I recommend you simply replace it.

 

[roald 2]

yes i have the blue and purple wire attached under the printer with the 12v battery the cable is oke.

i try to order the BD679 darlington transistor replace it, i let you know if it have solve the problem thanks for your fast help

 

[roald 2]

i found different types on the same number BD679 by Farnell which one i must choose ?

http://nl.farnell.com/jsp/search/browse.jsp;jsessionid=GGVEOZRFQOBN2CQLCIQZPQQ?N=0&Ntk=gensearch&Ntt=BD679&Ntx=mode+matchallpartial&exposeLevel2Refinement=true&suggestions=false&ref=globalsearch&_requestid=263842

 

[gr5 2,173]

They all look fine.

 

[chopmeister 0]

My darlington also blew up. I can't find a BD679, but I could get a BD683, is that ok for a replacement?

 

[gr5 2,173]

I looked at the spec sheet and the BD683 looks fine.

 

[chopmeister 0]

That's great, thanks! BTW, can I run the printer (for printing ABS) with the darlington busted without frying anything else?

 

[gr5 2,173]

In theory it could damage the arduino I think (I didn't look at the schematic just yet though). So I would recommend removing the transistor.

You can usually print without fan, especially large parts but no fan can make some things worse:

overhangs

top surfaces might bulbble

bridging

Or if you are printing something small, less than 10 seconds per layer, then the fan is a huge help.