Incorrect Extruder stepper motor wiring killed my Rambo?

So, while trying to get the Biqu H2 working, everything was initially great, but it was working in reverse. Easy enough fix, but when swapping wires to get the direction correct, I think I swapped the wrong two wires. When I reconnected it, let it heat up, and tried to move it a few mm, the motor vibrated and kinda jiggled a bit. I shut it down, double-checked and re-wired according to the wiring diagrams, and plugged it back it. This time, when I tried to move the extruder, I got a single “clunk” out of it, and nothing more. I powered down again, and reconnected the stock extruder. It’s now vibrating instead of rotating now.

Is there anything short of a new board that’ll fix it?

The driver chip is a sensitive beast because it can deliver a lot of current. I am not sure which wires were reversed, but if it created a short, that would fry the chip. A brief look at the schematic shows the driver chip for the extruder is the same as for the x, y, & z stepper motors. You may be able to verify that the driver is good or bad by connecting a different stepper to it… it’ll take a little thinking to do the test. But then you can know it’s the board, or maybe the motor.

If you decide to get a new PCB, I can use your scrap board to takes parts to repair a Rambo that has a dead Z driver chip.

I’ll be doing a simple change to the pins.h and recompiling marlin to use the secondary extruder driver to keep the board going in single-extruder only mode. If your board with a dead z driver is only used in single-extruder mode, you can do the change to the same pins.h configuration and build marlin to use that second extruder driver for your Z. It’s just 3 numbers that get swapped around and recompile.

I did pick up a Octopus 1.1 board though, which I’m working on programming for the Taz. If it were easier to swap between the two boards, I’d just set one board up for dual 2.85mm extrusion and the other for 1.75mm single extruder mode.

Oh, you are clever. I wish my board had a second extruder chip, but alas.

If you run across any scrap rambos, let me know. All I need is a driver chip (A4982)

So the rebuild wasn’t bad, I followed the guide @cdsmith posted, and swapped the E0 pins with the E1 pins in pins_RAMBO.h, initially I thought it’d just be 3 numbers, but there were also the microstepper and digipot channels, so just search that file for E0 and make sure you switch them all.

If anyone else needs it and doesn’t want to go through the steps of building it: here’s custom firmware to use E1 as E0. Taz 6 universal extruder driver swap.hex - Google Drive

Just power down, pull the E0 connection and E1 connections, on the board. Leave E1 disconnected and plug E0 where E1 was, boot up the machine and load the custom firmware.