Out of business!

Until now all of my problems have had to do with trying to make some kind of a change or trying to understand something. This post has to do with suddenly being out of business. And while I'm mostly a hobbyist I'm also in the middle of developing a product which will be marketed to hospitals to be used in emergency situations. So I hope I can resolve this quickly. My X axis has gone crazy. Right smack in the middle of making a part it started making a grinding sound switching directions back and forth ignoring the g-code and spoiling the piece. A few times when this happened I clicked on STOP and then maneuvered the axis with the keyboard. When moving the axis that way I continue to get the grinding OR I get a faint sound from the motor that produces no movement. I ruled out a faulty g-code by writing a simple program that would have it going from X north to X south 20 times. During that program it repeated the aforementioned behavior. So it seems to me that I must have a bad Gecko or a bad motor. Does anyone know how I can definitively determine if it's the motor without swapping it with another axis. My Y motor won't work because it has two shafts while my X only has one. The Z axis might take hours to show up as defective because it doesn't move much. The absence of failure on the X axis with the Z motor would leave me wondering if it just hadn't failed "yet". Would appreciate any advice on how to know for sure if it's the motor. PS: Motors are 640oz

Motors rarely go bad.

Only time I have seen motors go bad was when they got too hot.

To hot is when you can smell the varnish melting on the wires inside the motor.

To hot is when water sizzles on the motor casing.

99.9 percent of the time the Gecko module has gone bad.

Unplugged, power off. Motor disconnected from Gecko Module.

Measure the resistance between the Phase A and B, and Phase C and D.

If they are different, the Gecko is definitely bad.

If either is low resistance, less than 50 ohms, the Gecko is definitely bad.

The symptom you describe occurs when one of the motor phase drivers has gone bad in the Gecko Module. Usually you smell the bad module, but not always.

Dennis
www.super-tech.com

Is this a stepper motor? or closed loop servos? my guess is steppers, and your accel and decel AND/OR rapid traverse is set to fast! if the stepper motors are set to accel to fast, they will just twitch a little and not go anywhere. and do what you are describing. This could happen even if everything was perfect for the last year, then someone didnt notice the ways didn't have oil on them and they are dry, changing the conditions. If not the case, try to add more information, to this post, about your cnc.

So MR IQChallenged,

You bail out of this thread:

http://www.cnczone.com/forums/showth...t=59994&page=4

amd start a new one leaving me hanging on your keyboard jog problem. I'm

done with you. How rude. :(

Quote:

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Originally Posted by Mike Stevenson

So MR IQChallenged,

You bail out of this thread:

http://www.cnczone.com/forums/showth...t=59994&page=4

amd start a new one leaving me hanging on your keyboard jog problem. I'm

done with you. How rude. :(

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I hope you're kidding. I appreciate all help or attempts to help. That's why I send cash to various instituions and vendors of CNC freeware. I support my hobby. Quite often I have to leave something up in the air so I can go to work or go to bed. I work 12 hour shifts which amount to 13 hour shifts and right now I'm working 7p-7a. As you and I and others were discussing my keyboard problem I was simultaneously discussing it on the Mach Support forum which had me doing meter checks and all matter of troubleshooting. Then I had to leave them hanging for issues in "my other life" (the one that has nothing to do with CNC). Now suddenly the hospital wants their part finished so I had to revert to my old computer (the one without the keyboard problem). No new windows computer, no Mac computer. So what happens? Now my CNC with all it's stone-reliable components as gone south on me. So now that takes priority.

Both pairs of wires showing about 1000 ohms. Hard to say for sure because my digital meter won't work (what else). I will now check the motor phases.

Quote:

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Originally Posted by IQChallenged

Both pairs of wires showing about 1000 ohms. Hard to say for sure because my digital meter won't work (what else). I will now check the motor phases.

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Both pairs of wires to motor show zero ohms. I probably need to change hobbies.

IQ,

Are these drives stepper or servo? I need to know so I can tell you how to do a MOSFET diagnostic. The MOSFETs don't just fail, so something had to trigger it, most likely a short of some sort on the power supply cables.

Marcus Freimanis

Quote:

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Originally Posted by CoAMarcus

IQ,

Are these drives stepper or servo? I need to know so I can tell you how to do a MOSFET diagnostic. The MOSFETs don't just fail, so something had to trigger it, most likely a short of some sort on the power supply cables.

Marcus Freimanis

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Please don't leave. Just now logged on. Gonna put together a post.

Just now finished switching my motors (X and Z). Figured I let the Z do some fast up and down to see if it would do bad with the X motor. It did fine. Conclusion: Nothing wrong with X motor. Then I put the X axis through its paces with the Z motor. Problem recurred. Grinding and attempting to change course. Conclusion: Something other than the motor. Important to note that this system has been stone reliable for a year or longer with lots of use. This is new and sudden.

PS: These are 640 oz stepper motors from hobbycnc. Gecko 201s.

IQ,

Take your multimeter and set it to Ohms. A digital meter works best here. Now, take the ground lead on the multimeter and connect it to terminal 1 (power GND) and connect the positive lead to terminal 3. Make sure it does not read below 100KOhms, and move the positive to terminal 4. Do the same thing and move it to terminal 5 and then 6.

Now move your ground lead to terminal 2 (PS +), and do the same test from terminals 3 to 6. If any of them read below 100KOhms, and if they do it will generally read about 10 ohms or open, then the MOSFET is blown. You can send the drive back to us if you are uncertain and we can test it here slightly more rigorously and repair it if possible.

You can feel free to give me a call if you want to go over more options at (714) 832-8874.

Marcus Freimanis

Will do. I sent you a driver once before. I had destroyed it by accident. I realize you have to check it to be sure, but, does it sound like a driver problem? I'm assuming that's all that's left.

IQ,

If you call we can figure it out pretty quickly. From what it sounds like right now, the drive is most likely the problem. Now, what you have to figure out is what caused the drive to fail to begin with. It sounds like either a breakout board wiring or power supply wiring problem. I highly suggest you check both to see if there is a short anywhere, or if there is any exposed wire.

Marcus Freimanis

Quote:

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Originally Posted by CoAMarcus

IQ, From what it sounds like right now, the drive is most likely the problem. Marcus Freimanis

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I think I found the problem and fixed it. I ran a pretty lengthy routine afterwards without incident. As I was removing the Gecko I noticed the screws used to hold the wires were lose. Well, they weren't actually lose but there was what I would call "a scant amount of torque". I think there could have certainly been some resistance. I've noticed that these kinds of connectors will always tighten just a little bit more and that's not good in my opinion. I'm always afraid I'm going to strip them but you never really get the good solid feel. Maybe if the blocks were metal instead of plastic they would feel better. Anyhow, I only had a short period of time to verify the repair. I'll have to put it through its paces later. I will post my final assessment for the purpose of archiving to help others.

Hey guys. It is fixed. It would be fun to put a variable resistor inline to replicate lose connections to see just how much it takes to cause things to go crazy and precisely how the problems manifest. With me it was a noise and changing of directions. I guess I'm lucky it didn't blow something. Thanks for all the input. Keem 'em tight.