Mini Rambo bad extruder driver?

Had a failed print today, but not as expected. It seems the extruder gear was not moving well and had a kind of jerky motion to it so it was not extruding correctly. I figured it was probably the little gear that was loose and i think it was a little loose, but that did not fix the problem.

After i shutdown my machine and repowered it to test again the motor now does not have the jerky motion, but it makes a strange higher pitch noise that ii have never heard before (almost sounds like the motor is broken), but the gear moves, although i suspect it’s not moving as far as it should. Like perhaps not enough current is getting to the motor.

I tried switching the cable to the x-axis driver and “moving my x-axis” to test the extruder and the extruder works fine and actually sounds different. Considering the motor works fine on a different driver and there is an audible difference i am assuming my extruder driver on my Mini Rambo board is in the process of going bad and probably at this point unusable. My Mini Rambo does not have heat sinks on the stepper drivers, but i was seriously considering buying some the other day. Did it just get too hot and fry itself?

Thoughts? Is it time for a new Mini Rambo board? Is there anyone who does Mini Rambo repair work that would be cheaper than buying a whole new board? I don’t have the tools or the expertise to replace a surface mount driver chip, but that’s probably all that this board really needs to be functional again. I hate to just throw an 80% working board in the junk pile.

I have a used but good Mini Rambo board, its version 1.0a though, not sure what yours is or the changes made between versions. I could sell it for 50 shipped

Itworks3d also sells them use but they have no stock currently

Mine is one of the early revisions and was actually originally used from ITWorks. It was working fine until yesterday. Let me think about it for a bit, but i may take you up on your offer. I think the only difference is the newer ones just have a usable LCD port while the early ones did not.

It’s just strange that the board still seems to function. I would have thought the driver would be an all or nothing type of deal. The extruder driver still moves the motor it just doesn’t sound like it did before and makes the motor sound like gears are grinding inside. i’d be reluctant to trust it when printing. When moving the extruder motor to another driver it sounds fine. Also when moving a different motor to the presumably bad driver it also sounds okay. It’s just this particular motor on this particular driver. Weird.

So i got another mini-rambo from Keebie81. Thanks for that by the way.

But i think my extruder motor is still making a strange noise. Perhaps that means it was not the stepper driver going bad, but my motor going bad instead? Anyone have any thoughts? Is this a common problem? I know some said there was a bad batch of stepper motors awhile back with breaking shafts. I havn’t checked my motor, but i wouldn’t think it would turn at all if that was the case, but i don’t think it’s turning as much as it should be.

I’m using the half-stepper from Lulzbot.

Should i be using a full stepper instead. Is there a warranty on parts bought from the lulzbot store. Meaning is there a warranty on just the stepper as my machine was built myself?

There were some bad mini motors in a few of the ones that went out. I would recommend pulling the motor off and see if the shaft appears to be cracked. The ones that have failed seem to still kind of operate.

well, i checked it out. Physically it looks fine. It just sounds horrible when telling it to extrude or reverse, but seems to function. I still think i should probably get a new motor. But for now i’m going to try a dimensional accuracy print from the lulzbot files.

Well i don’t know know. It seems to sound okay while printing with the new board. But honestly i don’t think the new board is any different than the old one. Strange. Maybe it just all needed some tender care and cleaning. who knows. I guess i will just keep an eye or ear on it for now.