Author Topic: X axis problem  (Read 18743 times)

phonoplug

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Re: X axis problem
« Reply #15 on: September 09, 2015, 02:11:41 PM »
Yeah that'll be the older type if its got a toroidal in it. The newer ones are a lot smaller and use 2x switch mode PSUs, but critically, the 4 drive cards are all connected to a main board via short crimped (not IDC) jumper cables. The connectors out of the box are all on this main PCB so large wiring loom is gone. Looks like this inside:

The connectors I used were all from Toby. Crimps: 1900-TGB-L, housings 1800-H05 and 1800-H10. They are not the correct connectors for the header but they fit ok just don't have the friction lock. You could use good old Molex KK connectors (as in pic), but the crimps only touch one face of the pin, whereas the 1900-TGB ones contact at least 2 sides. For me that was preferable.

phonoplug

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Re: X axis problem
« Reply #16 on: September 09, 2015, 02:20:15 PM »
Just seen your pictures. Nice bit of veroboard in there! ;D
Ok thats definitely an old one, and I'd dare to say a very old one. Subsequent to yours they started to put two transformers in there. Then they made a proper job of it (see the pic I posted few mins ago).

Clearly the wiring was poorly designed for it to end up like that. The power for ALL the drives comes down that one thin wire and is daisy-chained along. Therefore the power for all drives is actually conducted into that first board on one pin, the out of that board and onto the next on another pin. Very bad idea. If you fancy re-wiring I'd suggest taking power wires from each drive card direct to the source, and not daisy chaining it like that. On later machines with 2 transformers at least the daisy chaining was only to 2 boards, not 4 like this.

You should be ok without having had any damage done, other than to the connectors. After all it was all working, other than a slightly rough sound. As that is the power connection, any damage I would expect would result in one or all axis being dead (no power)

arvydas

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Re: X axis problem
« Reply #17 on: September 09, 2015, 02:39:04 PM »
Yeah, veroboard is a piece of art in itself. ;D It looks like there have been repairs done on the controller board, because the cables in the IDC power connector on the veroboard have been cut and the soldered directly to the veroboard. I will have to do a proper job to rewire everything. It's an utter mess.

This makes a lot of sense now. The placement kept degrading over prolonged usage of the machine. I think that the poor connector got hotter and hotter until the resistance increased so much that there was not enough power supplied for the motors. I noticed it yesterday that machine started fine, but then by the end of placing 10 panels it started making noises again. Also makes sense why machine was struggling to place at higher speeds.

Thanks for all the tips phonoplug. Very very much appreciated! It does look that the stepper motor controllers should be intact, just a matter of sorting out proper wiring. Have plenty of KK crimps, just need to order now suitable housings, lot's of proper thick wire and get on with full rewiring :-)

arvydas

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Re: X axis problem
« Reply #18 on: September 09, 2015, 06:58:28 PM »
Ordered a bunch of crimps, housings and replacement header for the 12 pin on the driver board which got badly damaged. Decided to go with the Molex parts that are supposed to mate correctly with the headers.

arvydas

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Re: X axis problem
« Reply #19 on: September 11, 2015, 01:06:44 PM »
Just replaced all of the connectors and wired each motor driver directly from the power supply. Hooked up to the machine and the X axis buzzing is completely gone! The Z axis no longer has this very loud buzzing sound too which I thought was normal for the machine. I'm now certain Z axis was the last in the chain and it got the least amount of power which made it struggle to run the stepper motor. Still managed to place though. Now all axis movement is as smooth as it should be.

Finally I need to zip tie everything back to be safe and secure and should be back in business! Thank you so much for your help guys, you are awesome!

Wondering if it would be worth for me to improve the power supply for the motors. Would like to eventually get rid of the toroid and silly veroboard. Is it possible to acquire the power supply together with power module for the machine? Wondering if it's even worth doing that if machine will be running just fine.

Mike

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Re: X axis problem
« Reply #20 on: September 11, 2015, 04:29:03 PM »
I think an "ain't broke- don't fix" approach is best - as long as your mains voltage isn't unstable the toroids work just fine, and probably deal more gracefully than a switchmode with transient loads and load-dumps from deceleration.
 

Jason

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Re: X axis problem
« Reply #21 on: December 13, 2015, 12:27:03 AM »
Just been having similar 50Hz buzzing superimposed on the normal motor sound.
After re-reading this thread I 'scoped out the 36VDC and it had 5V of ripple on it  :o
Popped the bench PSU on it and the buzzing disappeared.
This one is also a torroidal PSU so I'm going to replace the 10000uF cap and also
tie the final connector back to the fuse board making it a ring rather than a
daisy-chain.
Also going to beef up the cable from the junction block where the torroid output
connects to two skinny wires which then go up to the bridge-rec.

arvydas

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Re: X axis problem
« Reply #22 on: January 25, 2016, 11:49:04 AM »
I'm still having buzzing issues on the X axis and will check the power with a scope.