Welcome to the SeeMeCNC Community

Hey all,
I've gotten my kit assembled, but have been trying to track down a short (or something? ) with the hot end, I think, anyway...

I've been blowing the Logic 5A fuse on the Rambo, and soldered in some plugs so I can connect cheaper 5A car fuses anyway. It blows as soon as I hit "Heat On" for the extruder in Repetier.

I was able to get this working once and went through a PID calibration, but haven't had any luck since.

However, I'm not sure if this is actually in the hot end, if I disconnect the positive and negative leads to the resistors, I still blow the 5A fuse as soon as I turn the hot end on. And occasionally when just fiddling around with the printer with the hot end of, the Rambo will reboot.

The + and - wires aren't shorted themselves in the tower (or anywhere else), I've checked that.

Other ideas for troubleshooting?
Thanks!

Well, if it were the hot end, I'd say measure the resistance between the two wires after disconnecting them from the Rambo.
But, you also said it happens when the hot end is not connected, which would indicate the real problem is NOT in the hot end at all.

Next step would be to disconnect from the Rambo all the wires for the extruder, heat and fan outputs and see if it still happens when you enable that output. That eliminates the possibility of misguided strands from any of your wires. If it still blows, there's got to be some internal short on the Rambo. Ask for a replacement board in that case, I doubt its anything you did. If it doesn't blow, start putting things back until it either works or you find the problem.

If you're desperate to get things working (before sending the board back), you could try reconfiguring the firmware to use the other extruder output.

Please post a photo of the hot end that shows the wire connections to the resistors.

g.

check your fan wires... if the fan wires short out, they will also blow that fuse, and when you say it blows when you turn on your hotend, I would guess the peek fan is at fault... disconnect the peek fan from the rambo and try to turn on the heat, if it doesnt blow the fuse, its thoes wires, alternately if it does blow, reconnect them, and disconnect the heating resistor wires and turn on the heat, if the peek fan kicks on, and doesnt blow the fuse, it would be the resistor wires...

Guanu