1 Amp fuse Blowing

[oddjob]

Hi All,

I made an error on a new build with polarity crossed and blew the 1 and 7.5 amp fuses. I corrected the issue and I'm now having an issue with the 1 amp fuse blows under heater load. It's a dual extruder (converted Cubex Duo) which I'm I am running 2 x E3D V6 hotends. I find I am able to Auto tune the heaters on the hotends, however when I try to heat a tool the 1 amp fuse blows. Any pointers greatly appreciated.

[Veti]

the 1amp fuse is for the fans.

does the fuse still blow if you disconnect all the fans?

[oddjob]

Hi Veti,

Thanks for your input. Unfortunately yes the 1 Amp fuse blows even if the fans are disconnected. I've also connected the fans to the always on an they seem to function correctly.

[Veti]

and all fan outputs work fine before heating?

[oddjob]

@Veti

I've not checked the fan outputs. I have checked the fans operate on the always on outputs and they were fine. The fans also work when I auto tune the Hotends.

The fuse blows when I request heat to be applied to the hotend whether from manual input or from running the preheat macro.

[oddjob]

Hi Again Veti,

I've not checked the fan outputs. I have checked the fans operate on the always on outputs and they were fine. The fans also work when I auto tune the Hotends.

The fuse blows when I request heat to be applied to the hotend whether from manual input or from running the preheat macro.

[Veti]

my thought was along the lines of the pwm fan mosfet being blown. and when for example the part cooling fan turns on, it creates a short circuit.

[oddjob]

Thanks for the insight really appreciated, I'll look at testing the mosfet.

[dc42]

Are you certain that you didn't get the fuses swapped? Turning a heater on shouldn't blow the fan fuse.

[oddjob]

@dc42 Yes, absolutely correct fuses swapped, now running fine. Thanks for your insight, very much appreciated.