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Squirrel
21st July 2008, 10:41 PM
Have been trialling my cnc router for the past 4 weeks (time permitting) and all has been running exceptionally well. Currently using the vectric Cut2D program with no issues.
The problem I am currently experiencing started when I tried to make up a centering probe. My probe didn't work, but this problem started about the same time, but I don't think it is the cause.
What happens is that the Z axis jitters when trying to move it. When I say jittering, if you move it in a plus direction, it will go a couple of turns then change directions then go minus then plus etc then stop. After this happened the first time I changed all the settings back to normal (with out the probe) and re-booted everything. This seemed to fix the problem.
But now it has started again and I don't know why. I have change my cabling with one of the other axises and found it does it on the other direction, so it is definately not a stepper.
Before I start checking the circuit board with my multimeter, I was wondering if this has been experienced by others.

Squirrel..

echnidna
21st July 2008, 11:15 PM
it sounds like a software problem to me.

rodm
21st July 2008, 11:31 PM
Hi Squirrel,
I assume the probe is still not connected but the problem has re-appeared.

There is no other way than to methodically trouble shoot this.
You say when you change cables from another axis it does it in the opposite direction - are you talking about the Z axis still - meaning the problem stays with the Z axis and does not shift with the cable change.

I stay at the computer if you want to keep going on this.

Squirrel
22nd July 2008, 11:31 AM
Rod,
Thanks for your offer to help and I will take you up on it. The only problem at the moment is the machine is at my uncles (partner in crime) whilst I have been working at the WYD08 gig. This doesn't finish for me until next week.
Yes, the probe has been removed and sorry for the confusion with the change of axis bit. What I was trying to say is that when I changed the cables it did the same thing on the new axis. To me the true novice, it does sound like it is software because the screw changes directions by its self, it will go + - + - then stop. Will get my uncle to re-install mach3 and eliminate all options one by one. I'm hoping that I am not the only idiot to replace a burnt out circuit board for the second time.

Rick

rodm
22nd July 2008, 12:03 PM
Hi Rick,
I hate to be the bearer of bad news but I have a gut feeling it might be a another board. I have seen this in action and it was a burnt chip on the board. :(

Rather than jump to conclusions though test your lead with a multimeter (remove it from the board first). Make sure there is no leakage between wires and to the plugs.
Check your motor tuning. If this is set way too high you can get some unpredictable things happeneing.

Wiring is where most things go wrong so make sure you have good connecotors or solder the joints and insulate well with heat shrink tube.

I don't think the probe caused the problem (but I have been wrong before) as the parallel port input pins on the Xylotex board are straight through. It would have more than likely cause a problem with your computer than with the board. Perhaps hook up another computer if you can just to eliminate the computer parallel port as an issue. This will also give you an opportunity to set all your pins and motor tuning from scratch. Mach3 retains your machine profile when you load new software unless you delete the entire Mach3 directory first.

If anything new happens get back on here and I'll rattle my memory bank in case it triggers a new idea.

Greg and Sean if you are around feel free to add your thoughts on this.

echnidna
22nd July 2008, 12:44 PM
One thing to try is to slow your motor speeed right down, if the problem goes away then, you may need to add a little friction to your z axis to reduce harmonic vibrations

crocky
22nd July 2008, 12:49 PM
Sounds like you may have problem :(

Rod has pretty well covered anything I could think of too. The important thing is to be SURE that you have no interuption in the wires to the stepper motors, not even for a split second.

You could check that the heatsinks are still on the chips too, a couple of mine had fallen off and the drive board had died because of it :(

I have a new spare board if you need one....

Squirrel
22nd July 2008, 01:29 PM
Thanks guys for the replies.
Rod, my uncle reloaded an older version of Mach3 because of the reasons stated and manually checked all the settings, this didn't work. He also attached a different computer to the router, this made a little difference and this may become confusing. We have the z axis set up with the page up and page down buttons to drive the axis, on the new computer whilst pressing the p-dwn (or p-up) it would work normal then when at different times whilst re-pressing the same button the axis will go in the opposite direction. Hope you understand what I am talking about, it didn't jitter but would change directions when a button is re-pressed. Also the stepper sounded as if it was laboring, the speed was reduced without any benefit.
It might be a case of buying a new board, which wont be a big issue as we were in the progress of chosing a new machine to build as this was only a test machine made of mdf and wood. ( and now we are going to want a machine each )
Crocky, if you want to sell your spare board I will be very interested as this will save time in waiting for delivery.
I'm going to have to check my soldering joints on my connectors, I used the 5 pin microphone plugs that Rod used and posted pictures of. Wasn't that a fiddly job.
Oh, bye the way and a tad late we have put a break out board on to protect some of the pins, will check this setup during the next couple of days.

Rick

crocky
22nd July 2008, 03:12 PM
Crocky, if you want to sell your spare board I will be very interested as this will save time in waiting for delivery.
Rick

Yep, you can have it... Still got the wrapping on it and also the instructions with xylotex tape :)

$155 US + post

Paypal is fine if you like :)

rodm
22nd July 2008, 03:32 PM
Hi Rick,
The keyboard inconistency with page up and page down is likely not the issue. It would be very unusual for a computer to send the wrong key code from a keyboard.
I think it is still related to the driver board, settings or a wiring problem.
The mike plugs can get a short between the pins and the casing if the tabs are bent or you have a pip of solder touching the case. Just put a multimeter beteeen the pins and the case and try to wiggle the wire a bit to see if you get any shorting. Push the pins towards the middle of the plug to make sure they are clear of the case. I always use a bit of heat shrink over each soldered wire to make sure there is no leakage.
Yes they are a pain to solder but they are a very robust fitting and can carry the power required to the motor.
The breakout board will only protect your computer if it has opto isolation and not the driver board.
It does still sound like a driver board to me though. Perhaps if you drop Jeff at Xylotex an email he might be able to confirm this and save you a bit of time in diagnosing the problem.

Squirrel
22nd July 2008, 08:57 PM
Thanks again guys,
I actually was kicking myself when I soldered up the connectors because I didn't use any heat shrink, what I actually did was cut up some insulating tape and wrap it individually around each pin. This was even more a pain than the soldering.
I think I will check this personally and if it doesn't work will send an email to Jeff again. He appears quite approachable from the last time I emailed him.

Rick

PS.. Crocky you just may have a deal, I will confirm it with a PM for your details in the next day or so.

WillyInBris
23rd July 2008, 01:24 AM
mmm Rod very much covered most of it I would be checking the wiring to start as well checking for earths and from end to end for a break in the wires.

Shrink tube is your best friend use it whenever possible.

Squirrel
23rd July 2008, 10:52 AM
Thanks again for the advice given, I have made up my mind that I will be re-soldering all the connectors and covering them with heat shrink.

Rick

Squirrel
24th July 2008, 10:26 AM
You guys are absolute geniuses.....

I resoldered my mike plug joints and covered them with heatshrink instead of electical tape.
As you guessed it, the problem is now fixed, from the very start you guys pinpointed my problem and gave the appropriate advice.

Happy days, now planning our second build, I'm leaning towards a 8020 aluminium frame.

Rick

rodm
24th July 2008, 01:00 PM
Hi Rick,
Glad to hear you fixed the problem.
I am sending you a link via PM to a style of driver that is tolerant of miswires and over voltage. You need to have a breakout board to connect these but it seems you have done that already so no extra cost there. They are very comparable to Xylotex but higher specification.