No control over 12v model cooling fans

[mark269 0]

Help Please. After a long trouble shooting search on my Ultimaker 2 extended. I replaced my 5v hot end cooling fan. but now I have no control of the 12v model cooling fans. I have no speed control and they are always on and will not shut off.

[Torgeir 280]

Hi @mark269,

 

As you hav an Ultimaker 2Extended, there is NO control of the nozzle cooling fan.

I did not know that an UM2ext had this feature built in, but "maybe" the later versions had?

 

The fan turns on when you turn the master on and go off when master is switched off!

So do not worry about that.

 

The factory built UM2+ have a feature thats turning this fan at approx 40 deg Celsius nozzle temperature.

 

What you say is correct for an "UM2Extended", the printer (I have), upgraded to a plus version later -but still have the old fan version.

 

If you do have the black feeder unit, this is the old version, however there "might" be a version of  UM2Ext with this feature included..?

 

Maybe someone else know somthing more about this issue?

 

But if this fan is running all the time, there is no problem of printing like this as the idea is to save the life lenght of this fan (during idling after print is finish) and reduce noice in idle mode. EG. when printer is on without printing.

 

PS. If there have been a kind of short circuit here, it is possible that the transistor controlling this circuit is on "all the time".

 

Thanks

Torgeir 

 

 

 

 

 

[mark269 0]

Thank you for your replay. when you say Nozzle cooling fan I assume you mean the single 5V fan, and you are correct that is always on. My problem is with the duel 12 volt Model/part cooling fans. which used to only come on after the second layer was laded down. Now they are always on from start to the finish of the print. And I have always had control of the fan speed/percentage until now. I thought it might be a circuit board problem. but I hope not. I did flash the farmwear and tried controlling my printer with my Simplafied3D slicer. Which now that i think about it, my have been the start of of my troubles.  is there a way to test the circuit board?

Edited January 12, 2023 by mark269

[Torgeir 280]

Hi @mark269,

 

As you hav an Ultimaker 2Extended, there is NO control of the nozzle cooling fan.

I did not know that an UM2ext had this feature built in, but maybe the later versions had?

 

The fan turns on when you turn the master on and go off when master is switched off!

So do not worry about that.

 

The factory built UM2+ have a feature thats turning this fan at approx 40 deg C.

 

What you say is correct for an "UM2Extended", the printer I have (upgraded to a plus version later but still have the old fan version).

 

If you do have the black feeder unit, this is the old version, however there "might" be a version of  UM2Ext with this feature included..?

 

Thanks

Torgeir 

 

 

 

 

 

[Torgeir 280]

Hi @mark269,

 

aha understood, well it is the ground side that¨is controlling the speed of those two fans.

This is indeed a good sign somehow.

If there is a constantly ground at the minus side of the fans, this will happend.

Actually such a short would not destroy your mother board!

But there is a change there is a constant ground present at the negative side of the fans.

Edit: There is allways 24VDC present when the power is on, but the ground side is controlled by the mother board. The board adjust the current to pass through here, hence controlling the fan speed.

There should be no ground present at the minus side when the connector for those two fan is removed.

It is very important to not try to move change anything in the wiring path, as this can "remove" the failure temporarly, to return later.. There might be a ground short somewhere, Did you have any issuer requiring repair in the head lately?  I'll ask this because often after maintenance or repair such thing often happen.

 

The id for this voltage is VCC/2 and is 24 VDC.  So the two 12 VDC fan are connected in serial.

So, the minus wire (connected to J14 pin 2) might be grounded all the time -or the driver transistor controlling the current is shorted.

This transistor is T1 P/N: BC817. 

 

So this wire might be shorted to ground at some place  -or the transistor T1 on the main board is shorted (internally shorted). 

 

Good luck.

 

Thanks

Torgeir

 

Edited January 12, 2023 by Torgeir
Text error, plus more information.