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I am replacing my old cracked, and not functioning resistors for the hot end. I used the instructions in the build assembly guide but they are still not working. Any replacement advice?

I have multi-testor i can test tomorrow (since its not here in the shop).

I didnt use the silicone yet but plan to. Does it need it for testing?

I didnt use the crimp connector i just soldered the leads.

What happens if it leads touch the extruder body (mine dont)?

Tips tricks, encouragement?

Make absolutely sure the leads are not shorting somewhere. Are you using tubing for each of the leads from the thermistor?

the RTK Silicone just helps transfer heat, resulting in a more accurate temperature reading.

If the leads touch the extruder body, not only could they short (if not within tubing) they can conduct enough heat up to your solder and melt it.

I've gotten away with soldering, but I did use 90% lead solder (melts at ~270C instead of ~180C for standard solders). Remember, that solder joint is on a wire an an inch away from and connected directly to the heat source that's going to heat your hot-end up to 240C.

That said, I won't be using resistors when it's time to replace. I'll go with one of the ceramic heater cartridges that are cheap and available these days.

Thanks all. Good advice. Is there any physical evidence of shorted resistors until I get my multitester here?

Look at the Rambo Card and verify that the extruder LED is lighting. It is a red LED on the top left of the card, 1st from the left I think. Also take a look at F4, it is the large automotive fuse on the top right.

If these check out, run the wires all the way back to the resistors starting with the power supply wires, to the Rambo, to the hot end. Look for loose connections and breaks especially where the wires exit the columns.

If all looks good disconnect one end of the resistors and check the resistance of the pair and the resistance of each one. I think that I remember that each resistor should be 6.8 ohms individually and 3.4 ohms when paralleled. Also look for 12VDC at the resistors.

Good Hunting.

nitewatchman

fuse is good LED is shining nice and red. Wires are good. I will probably replace them just to be safe though. Next will be testing with multimeters. I ordered heat cartridges too