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rbsears
03-04-2001, 11:58 AM
I just got my shopbot up and running, everything seems to be running right going thru all the test but when the motors are running there is a small thump about every revolution also there is a slight (small) jerk about every revolution. I couldn't find anything in troubleshooting about this. Any help on this matter would be appreciated.
Thanks
Richard

bill.young
03-04-2001, 12:11 PM
Richard,

If it happens at every revolution of the stepper motor, I would check the pinion gears to make sure that they don't have a bad spot on one of the teeth or something caught in one of the teeth.

I'm not sure about the newer tools, but some of the pinion gears in the past had two set screws that went through the toothed section of the pinion. If yours is like that, make sure that both set screws are driven in so that they can't hit the rack.

Bill

rbsears
03-04-2001, 12:51 PM
Bill,
I thought of that too but the newer gears have set screws on the collar, it does it even on the z axis which come from Shopbot aready assembled. Do I need to calibrate anything in the program?
Richard

rbsears
03-04-2001, 03:23 PM
I watched the gears run alittle closer and the thumping noise is about every 1/4 of a turn, it happens in all the motors. Could I unhook the springs from the x drive and run the motors away from the pinion just to see if the noise is still there or would this mess everything up?

Richard

rbsears
03-04-2001, 09:50 PM
Found out that I hadn't changed my unit value as required by Shopbot. When all else fails read the instructions.
Richard

birdsofplay
03-05-2001, 12:39 PM
First if you dont like the noise but everything else is ok, THEN turn on the ROUTER :-)

Second, I too have noticed this but continue to operate anyway.

It's kinda like a slight hesitation or delay that I notice when doing router-off long-jogs at higher speeds.

I suspect it's a "timing thang" inside the microcontroller that is issueing the steps/phases to the motor driver boards. Like maybe an interrupt routine gets control for a small slice of Microcontroller time.

These newer motors are so large/massive that any small change in "repetitive" events can easily be heard/detected.

Unless you're actually missing steps and/or registration dont loose any sleep.

roney
03-05-2001, 08:39 PM
Richard,
Had a similar problem early on, did you go in and change the values in your default program also?
JRC

rbsears
03-05-2001, 10:38 PM
JRC
Do you remember what you set your vs and vr setting at, I tried setting values at different setting and didn't seem to help. As far as me setting values in the default program I not for sure if it was the default program.
Richard

jmw60010@yahoo.com
10-06-2002, 06:16 PM
The stepper motor that controls the Y axis rapidly alternates rotation slightly between the positive and negative direction instead of moving in just one direction. Any suggestions?

Jay Wiese

jmw60010@yahoo.com
10-06-2002, 06:23 PM
Oops, I forgot to mention that the machine is a PRT36 that was shipped in January of 2001.

Jay Wiese

swimsNOSPAM@mindspring.com
10-06-2002, 11:53 PM
I had a similar problem with my z axis, which turned out to be a loose connector.

tlempicke
10-07-2002, 07:07 AM
First check all of your connections quite carefully. A loose connection can fry a chip and put you down for a period of time while you get a new (And quite expensive) one.
Try this;
disconnect all four plugs from the driver board. Now put the axis you are trying to troubleshoot in the center of its travel and connect it to a DIFFERENT channel in the box. In other words if your Y axis is in doubt put it on the Z or the X plug. Make sure you have the power off of the system when you are swapping plugs.

Does the problem persist? If so it probably is in the wiring after the plug or in the motor. If the problem does not re-appear then use one of the known good motors on the channel where you had the problem. If you still have it the problem must be in the driver.

There is no reason in the world why you can not load a file and let it run with just one axis connected. Just make sure that the machine has enough travel so that it does not bump the end stops.

danhamm@abccom.bc.ca
10-07-2002, 11:37 PM
Jay I had this same problem when I lost a resistor
on the older PR96 circuit board, a disconnected
wire would do the same thing it just rotated a small amount back and forth..maybe do a resistance test and see if you have any opens...

jmw60010@yahoo.com
10-08-2002, 04:35 PM
Dan, Tom, Steve,

Thanks for the suggestions. It looks like I have a fried driver ($150).

toys
10-08-2002, 05:16 PM
Jay, Are you sure you can't get the driver chip for less then that? $150 sounds like the price for the whole driver board. On my PR I have replaced the driver chips for about $12.00 It required desoldering the old chip and soldering in the new one.

tlempicke
10-08-2002, 05:51 PM
Shopbot just did a pretty nice thing for me in helping me out with a stepper motor problem. I don't want to do them out of revenue, but here is how I handled the same exact problem.

First off I did call Shopbot and they sent me out a new driver board the same day. Tool back in operation within 24 hours.

Went out on the web http://www.bdent.com/
and ordered a new driver chip. Got a couple of them while I was at it, since the shipping is almost as much as the chip.

Replacing the driver involves cutting the legs on the old one and using some compressed air while heating with a soldering pencil to get the holes clean. Try mounting the board in a drillpress vice and getting another guy to help. Make sure you are using a soldering pencil that is for electronics work. A nice chisel tip and about 900 deg. are what we used.

When you mount the new chip be careful. It will go in two different ways. If it is offset to one side you have it in backwards.

Solder all of the little legs to their respective pads and you have an extra channel for the next time you get ham handed.

toys
10-08-2002, 08:24 PM
You can also use a solder sucker or a braided soldier wick. With a solder sucker you push in the plunger heat the leg with soldiering iron until solder melts and push the button on the solder sucker. It vacuums away the solder. you don't need to cut the legs off with this method, but it would probably be quicker.

jmw60010@yahoo.com
10-15-2002, 04:39 PM
David and Tom,

I'll keep that in mind for the next time. Since high school kids use this machine, I'm fairly sure there will be a next time!

grant@shopbottools.com
10-15-2002, 05:27 PM
Jay, I think our friends in the ShopBot community here have done an excellent job troubleshooting your problems. However, it sounds to me like there may be more than one culprit at work. Your deceased y axis is most certainly a blown driver. However, the "hiccup" that you were noticing in motion sounds to me like the interference caused by certain device drivers or a network card. If you are still having this trouble after you get your driver fixed, I would send a problem.log to myself or the support inbox (support@shopbottools.com (mailto:support@shopbottools.com)) with some background info for us to have a look at it. Your problem.log, incidentally, is a file in your c:\sb200 folder. Just attach it to an email. If you have a network card on the computer, you might try physically removing it to see if that does anything. If none of this helps, or if you just want to discuss it, call 1-888-680-4466 and ask for Grant or Frank in support.

Jay Wiese
10-21-2002, 05:01 PM
Problem solved! Two days after I contacted ShopBot, I had the replacement driver in hand. It was very easy to replace, and our machine is running like a champ again. Thanks to all who offered suggestions.

ssexton@localnet.com
11-09-2002, 05:14 PM
Can anyone tell me the make and model of the stepper motors. I would love to buy a Shopbot for playing around with in the garage but can't justify the $$$. Maybe someday, I can still dream can't I.