Ebay Chinese Routers (CNC3040) - anyone purchased one of these machines recently?

Unless its`s possible to set some sort of safe area that reverses Z-axis in mach3?

Wiring does sound like the suspect, as price of copper has increased so has the thickness of the insualtion and thinness of conductor on some Chinese gear, looks like the right wire until strip it open.

Straightforward to test with multimeter between connectors of controller and stepper connector, give everything a good waggle and roll the axis by hand, look for open and short between wires.

let us know how you get on.

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Originally Posted by camhguh

i jog down it goes up and when i jog up it goes down

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If that's the only problem it implies the direction setting for Z in mach 3 is set the wrong way. Could try going to "Config"->"Ports & Pins"->"Motor Outputs" then changing "Dir LowActive" on the line for Z. However if it's working fine in another place that's not going to help you. The only things that can change the motor direction is the state of the direction pin on the stepper driver, or changing the polarity of either phase. The latter surely cannot happen, so I'd put a voltmeter on the Z-axis driver direction pin and see if it looks right.

Whereabouts are you in Nottingham? I'm at University of Nottingham so if you don't get it sorted today I'm happy to come and have a look as it shouldn't be far?

second coffee of day ;-) , dodgy stepper 101, change the connectors over on to another axis, see if problem follows driver or motor.

there is a way to reverse the motors in Mach without messing with pins and stuff. I have done it on my machine for both Axis.

it's in some sort of options and there is a table and one of the options in the table is Reverse and you can just change it from a cross to the Tick and it will be sorted.

I will find out for you later.

Thanks for your thoughts on the problem folks, much appreciated!

Will give some of those ideas a try later on when were finished milling out our latest batch of bits and pieces! Were somewhat constrained noisewise because of neighbours so have to be prudent.

The reversed direction was a joke right? I think it confused a few.

Anyway it does sound like wire, as said just move it to a malfunctioning position and test the continuity with a multi-meter. At the motor end you probably don't have access to the bare wire so you could push a pin through the wire insulation into the core and then you can test from that.

To be honest though, wire doesn't tend to break, the connection points do, at the plug and at the motor. You might end up needing to open the motor case to check where the wire joins.

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Originally Posted by Tenson

The reversed direction was a joke right? I think it confused a few.

Anyway it does sound like wire, as said just move it to a malfunctioning position and test the continuity with a multi-meter. At the motor end you probably don't have access to the bare wire so you could push a pin through the wire insulation into the core and then you can test from that.

To be honest though, wire doesn't tend to break, the connection points do, at the plug and at the motor. You might end up needing to open the motor case to check where the wire joins.

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No joke sadly, thats what it does. Starts out on z+ for instance then reverses to z- or other way round.

If i jog the gantry around i can feel that there is little power on the zaxis motor because i can move it manually until it gets to a position on the bed where power has obviously been restored, then it feels similar to the x y motors. Guessing that its a cable/connector problem of some sort. On closer inspection the cables do not look new and are probably reused.

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Originally Posted by camhguh

Well...guess what...we have a problem...after around four or five hours intermittent use the z axis is misbehaving....when i jog down it goes up and when i jog up it goes down...hehe not... bloody Chinese gremlins!!!

The odd thing is that we can move the gantry to a certain position on the bed and it works fine but within a limited area. Because we need the parts urgently we are running it for the moment in this manner but its a pita!

I think because it works ok in one area of the machine that the problem is most likely to be with the wiring and not the driver boards...at least im hoping so..because any issue with the wiring would be a lot easier to resolve!

Forgot to mention that we are using Mach3

Anyone come across a similar problem?

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Could be a dodgy keyboard and it's just coinsidense it happens to be working in one spot to the other. If you have another KB it's Certainly worth eliminating for what it takes.!!

Good point, mine didn't work right with the spindle running as it caused EMI. Have you been trying this with the spindle off?

Thanks for the input guys! Yes i have tried it with the spindle not running, didnt make any difference! As soon as its finished milling the current bits and pieces then will have a look to see if i can pin it down.

Thanks for the link Modcube...looks like its a known problem with these machines?....hope this one's the same...easy fix!