I just completed a 2'X6' CNC table and am having a parrallel port issue (I believe).  I initially installed Mach3 to an IBM T40 (1.4ghz) notebook and was fairly easy to get all three axis working ok.  A little problem though.  I could only get 30 RPM (3 Inch Per Minute w/ 10 pitch screws) as a maximum speed.

I moved a desktop to the garrage to see if the faster computer would work better (Intel Q9400 2.66ghz - Quad core processor).  The Y and Z axis work ok, but ONLY when I set the speed at 10 inch per minute and the X axis just hums and jerks back and forth no matter what I do (core speed set to 100).  Through trial and error I've found that the X axis output (likely LPT?) is out of sync with the rest of the outputs.  The computer had everything build onto the system board accept the parallel port.  I had purchased an add on card with the computer ($19 card off the shelf that works fine with my old laser priner). 

A secondary issue I'm having is the two axis that do work only work at the 10 inch per minute speed.  If I adjust the speed up or down the motion becomes VERY jerky or won't operate at all (just humms and jerks back and forth).

Is there a recommended add on parrallel port that is known to work good? (or a used brand / model of computer that is known to work) 

OR - Is there a way to get more than 30 RPM from the T40? (best solution).  The LPT check program that comes with Mach3 says the 25k core speed is the only speed it will work at.

Any assistance is much appreciated!

Thank you,
Jeff

Ok, I've gone back to the notebook and found that the X axis now does the same thing.  I've also moved the wiring for the X and Y axis and the same motor has the jerking movement.  At this point I'm pretty sure the motor is bad.

My only remaining issue is how to get the motors tuned to move either faster or slower than the 10 inch per minute.  I'll be using my table with a plasma cutter so controlling the speed is critical for various thickness metal.

I've experimented with different step and dir settings in the motor setup.  I've not noticed any difference in speed or how smooth the axis moves.

Thanks in advance,
Jeff

Notebooks/laptops generally don't work well with the parallel port. All the power savings stuff messes with the processor speed which screws Mach up. If you want to use the parallel port you would be better off to start with a fresh install of Windows on the Desktop machine and do the Mach optimization: http://machsupport.com/downloads/XP_Optimization.txt

If your set on using the laptop you would be better off to look at using a SmoothStepper: http://soigeneris.com/Warp9.aspx .

just hums and jerks back and forth no matter what I do (core speed set to 100).

If by 'core speed' you mean the kernel speed on the 'ports and pins' config page, then that's your problem. I would wager there are few  . . if any . . computers that can successfully run that speed, laptop or otherwise.

Set the kernel speed to the slowest setting (35k) and go into your laptop bios and turn off every 'power saver' setting you have available to you.

Artsoft says they 'do not support' running on laptops, but that does not mean that Mach will not function fine on a laptop. It depends entirely on the laptop and you have essentially a desktop computer. My wife's IBM notebook does this when it is in its docking station.

It is amusing to see the smoothstepper suggested as a 'solution' to a problem with Mach3 . . .

It is amusing to see the smoothstepper suggested as a 'solution' to a problem with Mach3 . . .

I don't know why. I bought my first SmoothStepper almost two years ago for a custom machine I was building. Since I did not know what PC would be running it and needed to gauruntee that it would work I went with the SmoothStepper. In the two years hence I have never looked back to using the parallel port. While there are a few features of Mach's parallel port driver the SS does not yet support it does do very well what 95% of most folks need.

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It is amusing to see the smoothstepper suggested as a 'solution' to a problem with Mach3 . . .

I bought my first SmoothStepper almost two years ago for a custom machine I was building.

Two years . . .  that's how old the 'current' manual is.

Forgive me Jeff, but since you are a dealer for the smoothstepper, methinks your opinion may not be completely unbiased. In the smoothstepper section as we speak . .  yet another unresolved problem.

I have to wonder why Warp9 listed as the moderator, yet they have zero participation?

Any 'opinion' is biased. 

I simply report the truth about various ways to solve a problem to let folks make an informed decision.

Any 'opinion' is biased. 

I simply report the truth about various ways to solve a problem to let folks make an informed decision.

Fair enough, Jeff.

Thanks for the information provided.  Through additional t-shooting I've found that the X axis motor is having some issues and not related to the driver, port or mach 3.  That said, I'm still having the speed issue. 

Is there a recommended computer that works best?  Used IBM and Dell computers are a dime a dozen so I'd be happy to pickup a computer to dedicate to the table if I knew of a model that works well.

Thanks again!
Jeff

It all depends on the motherboard used and perhaps the exact peripherals (as drivers may cause problems as well.)