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  #1  
Old Sun 16 March 2008, 20:06
cncb
Just call me: Brian
 
Connecticut
United States of America
One of the four motors not running properly - faulty Geckodrive 203V

Heres a copy/paste from the cnczone forum I posted earlier there. Hopefully since there are more than a few of you with the same or similar setup as me (geckos and pmdx) you might be able to shed some light.

After issues with 1 of the four geckos it came back fixed and works perfectly again; to bring up an issue that I have been having the entire time. My machine is a 4x4 hybrid, 4 305oz/in stepper motors, 4 gecko 203vs, 1 pmdx 122 bob, antek 56v psu and a few other electronic components and switches. 2 motors run single, individually in mach3. The last two run together, my Y axis (moving gantry) in sync. Right now i have the timing belt off to determine movement in the motors. Both motors power up and have worked but it has been inconsistent from the beginning. Sometimes they send step/dir signals, often times not. Also, everything appears to function well inside the controller, green across the board, lights function on the bob as if it was working, and this is all internal, I've switched up cables to motors (I have quick connect xlrs) and I've proven it is either the bob or the geckos.

Where I'm stuck is from there on. No problem, so tried jumpering the two motors /geckos on one set on the bob to see if it works; if it does than I can assume that the bob is bad and the Y2 pair (3 terminals) is bad. It worked for a few minutes, I left and shut it off to buy some more stuff at radio shack, now it won't go and work again. Still getting full power to the geckos, appropriate power to each pin, everything matches up or is at least close to one another in terms of voltage as per my multimeter. It just doesn't make sense to me. I have checked the wiring almost 10 times now, and replaced the wiring completely from geckos to motors and geckos to bob.

Anyone have any ideas on how I can either single out the gecko or the bob? Gecko is showing green, functioning like the other three, no issues. Bob is the same. I'm open to all ideas, I just want to get cutting. Will contact PMDX on Monday, just thought some of you might have ideas. Im pretty sure its the BOB though..

Thanks for your help everyone.
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  #2  
Old Mon 17 March 2008, 08:16
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
It looks to me like you might just have a connection problem. If you have an oscilloscope, look at the signals at the source (PMDX-122) and then look at the signals again at their connection points on the G203v. They should be the same. Verify that you have the G203v's signal ground firmly connected to the signal ground on the PMDX-122.

If you don't have access to an oscilloscope, see if you can find a logic probe at your local Radio Shack or electronics parts store. A logic probe shows the polarity of signals as well as the nature of the signal (pulsing, steady state, etc.). A digital multimeter can also be used, but most meters don't handle pulsing signals very well.

If you have too, you could even use two AA-batteries connected in series to test a G203v. Connect the ground end of the battery-pack to the ground line on the G203v and then just tap the Plus (+) end of the battery-pack to the direction or step connections on the G203v. You should see movement on the motor.

All of this assumes that you have the power connections to the G203v properly connected and that the stepper motor's coils are properly connected to the G203v.
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  #3  
Old Mon 17 March 2008, 16:11
cncb
Just call me: Brian
 
Connecticut
United States of America
Richards, Thanks for your lengthy reply, appreciate the help. I will tinker a bit more tonight and switch things around as reccomended by PMDX talking with them today. I need to isolate the problem to an individual component and then go from there. The gecko 203v has correct power, all pins are matching up with other 3 geckos I have, everything appears to be in order but isn't. I will take your advice though on the oscilloscope or stop by radio shack and see if they have a probe that you described. Thanks!
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  #4  
Old Tue 18 March 2008, 19:37
smreish
Just call me: Sean - #5, 28, 58 and others
 
Orlando, Florida
United States of America
Gosh,
It acts like a signal ground *loop* problem on the surface. Or a ground issue in general......Check your XLR panel mount to chassis on the pass-thru Brian. Is everything isolated? Does the motor on the bad channel work on a good channel? When you soldered the xlr....sometimes a stray solder joint will cause a cross talk/ground out issue. Check the pins against eachother, against ground, and against shell shield.

Just my quick thoughts.

Sean
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  #5  
Old Wed 19 March 2008, 03:35
cncb
Just call me: Brian
 
Connecticut
United States of America
Quote:
Originally Posted by smreish View Post
Gosh,
It acts like a signal ground *loop* problem on the surface. Or a ground issue in general......Check your XLR panel mount to chassis on the pass-thru Brian. Is everything isolated? Does the motor on the bad channel work on a good channel? When you soldered the xlr....sometimes a stray solder joint will cause a cross talk/ground out issue. Check the pins against eachother, against ground, and against shell shield.

Just my quick thoughts.

Sean
THanks Sean. Actually last night I figured it out and narrowed it down to the one geckodrive. It's got something wrong with it, will call today. I did it by switching around wires in the controller. I knew it was either the bob or gecko as switching the moor cables (y1 to y2) and vice versus worked fine. The problem was inside, then worked my way from the bob to the gecko, switching pairs on the pmdx and got the good y pair to work on what I considered the bad y pair so then I knew it wasn't the BOB (pmdx122). Down to the gecko I then paired up or pigtailed the phase wires onto one gecko (not recommended but doable according to geckodrive) for the purpose of testing and it worked fine again, all 4 motors. So then I knew it was the geckodrive, the third one that was acting up in the line of 4. Hopefully I can find a resolution and this won't be the 2nd of 4 bad geckos I purchased. Still my faith in geckodrive is high, their vampire drive is awesome and my other axis's run like butter.
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  #6  
Old Thu 06 November 2008, 22:05
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Brian, can you give us an update on that Gecko issue?
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  #7  
Old Fri 07 November 2008, 04:55
cncb
Just call me: Brian
 
Connecticut
United States of America
Had to think for a minute since you bumped such an old thread! According to geckodrive I was the first in like 10,000 units to have a bad opto-isolator on the 203v. Sent it back and they fixed it in speedy time. Still running 4 and they are working wonderfully; about to add another for my 4th axis.
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  #8  
Old Fri 07 November 2008, 05:12
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Blame Doug He mentioned this thread as a candidate for the Troubleshooting forum, and we needed the closure. Thanks for that feedback. You guys are lucky that you live close enough to the Geckodrive HQ and can send them back for evaluation - out here it is cheaper to just buy another
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  #9  
Old Sat 08 November 2008, 07:46
cncb
Just call me: Brian
 
Connecticut
United States of America
that's ok, better in this forum anyways. I really like the way you organize this forum; I know it is a lot of work to maintain but in the long run it has and will be better for people to find stuff.
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