Hot End Doesn't Heat Up

[Andrew83]

I'm having trouble getting the hot end to work on my printer. Thermistor accurately reads room temperature (around 26 c). LED on Rambo board lights up when I manually turn on "heat extruder" in Repetier. I've used a multimeter and get no reading at the terminals on the Rambo board while hot end is turned on, so I know it's not in the wiring or the resistors. I've gone through the firmware and can't find anything that would be holding it back from heating. The heat manager style is set for On/Off (Bang Bang). Any ideas? Everything else works great.---Rambo 1.1b board with latest Repetier firmware and Repetier Host software, single Steve's extruder and hot end with bowden tube and 100k thermistor (from SeeMeCNC).

[626Pilot]

If you disconnect the connector from the board and test for resistence, you should get 4 ohms. If you test for continuity, you should get a very small voltage drop, but it should NOT be 0.000. If you get 0 ohms, there's a short.

Is the LED that lights up red and directly under the connector for the extruder heat? With Heat Extruder turned on, what voltage do you measure across the connector? (Test at the metal screws on top of the wiring block.) You might want to pull your fuses with some tweezers and check for continuity - they look like this: http://www.mouser.com/Search/ProductDet ... 0448005.MR

[CJGerard]

I had a similar problem. I checked all my wiring and the board and everything checked out, but the resistors checked out at 50k ohms. So im now waiting on new resistors to try again.

[Andrew83]

Tested continuity on the nano2 ceramic fuses and the hot end fuse was bad. Hopefully that was it, but I'll have to double check the hot end resistors and wiring before starting it up again, as they could have been the cause of the bad fuse. Thanks for the info.

[spart]

check to see if your heat resister is wired wright as in twisted to the other one not back to it self i just did that move and got the same problem your having right down to blowing fuse

[m4r1n5]

Im having similar issues. My bed heats up, but not my hot end or fan. No red led comes on when either is "on", only the printer bed.