C10 Breakout board problem solved

[Bob Willson]

For the last year or so I have been building one of the MDF CNC machines and I had actually got it to the stage where it was physically finished and I had cut a road runner in a bit of hardboard. This was good apart from the fact that it seemed to be only 50mm square.

Then, I had to leave the project because there were other things that I had to do. About two weeks ago I needed another computer for something and I decided to use the 3gig Pentium4 that was just sitting under the house attached to the CNC. So, I reformatted the HDD, put Linux Ubuntu on it and solved my immediate problem. However, the sight of the CNC rekindled my interest and I decided to get it all going again. I had a Dell or two lying about so I decided to use one of them as the dedicated computer so I loaded a fresh install of XP with SP3 on it and put Mach3 back on as well. So far so good.

This was of course just the start of two weeks of frustration. The damned thing just would not respond in any way. So .. the first thing was to check that the parallel port was sending the correct signals. The CMOS assured me that the port was set for EPP, so that was all good. Next, checked the cable just in case it had come to some harm under the house. Nope, that also was good.
Lights came on on the C10 board and also on the 4030s and the motors all locked up, so they too were all working OK. At this point I decided to do a rewire of my limit switches just in case something had happened there. So I put in a triple light switch so that each axis had its own bypass and tried again. Whoa, I got movement out of the Z axis but none of the other axis. Is there something wrong with the setup of the motor outputs and inputs. Check everything again .. no, it is all correct and as it should be, All ports were correctly identified and correct values inserted and I had been over the boards numerous times ensuring that there were no loose wires and that no gremlins had come along and moved some wires about at random.

At this point I reasoned that as everything that was meant to be happening with the hardware side of things was all as it was meant to be then the problem must lie somewhere within the computer because as you may remember, the thing was working properly when I took its old computer away. So, ANOTHER computer, XP, SP3, MACH3, CMOS checked, ran Mach3 setup and port check .. brilliant. Plug in CNC and wohoo, I get movement on the X axis I press the left arrow to jog left .. she jog left, I press the right arrow to jog right .. she jog left. Still no movement on Y, but Z works properly. F***. What the hell is wrong with this machine. Check all the motor inputs and outputs again this time, I let Mach set its own limit switches. .. they were exactly what I had put in.

Spent three or four days on the net trying to find people that had a similar problem .. nothing.

Maybe I had damaged the C10 board somehow. I looked all over, but nowhere did I find symptoms similar to those which I was experiencing. I decided to buy new chips for C10 as they were cheap and would enable me to quickly reject the board as the suspect. In the interim I thought that if I swapped over the chips I could find any that were maybe a bit suss. So, I swapped the chips for the ones adjacent to them on the board and voila, it all worked like a bought one.

The SN74ACT245N chips are not mounted directly onto the C10 board, but rather they are in sockets so that they are easy to replace. But it would appear that thanks to the wet weather we have been enjoying over the last 1/2 year or so, some of the pins on the ICs had lost contact with the sockets and all I had to do was remove and replace them in order to fix the problem.

So all axis are now working as they should and I just need to set motor speeds as well as I am able and then just a year or so to learn the basics of the software so that the next roadrunner that I do is at least 300 mm square.

[rodm]

Hi Bob,
Thanks for sharing your problem solving - it helps us all to know these things.

The roadrunner is in inches so you have to scale it up to get a decent size or run your machine in imperial. By the way it is also an incomplete file as a couple of lines are missing from the code but you have to look hard to see it.

[Bob Willson]

Hi Rod
Thanks for that. So all I have to do is set the X, Y and Z axis to 25.4 times the normal and all will be well. .. Apart from the missing lines that is.

[rodm]

You got it but you might only want to do Z at 10 times.
Once you have scaled it hit the "regen toolpath" button and change to the "Toolpath" screen (button at top of screen) then have a look at the Program limits area. See attached area circled in red.
This is something everyone should do before cutting the job because it tells you the cutting envelope. Match this to your machine limits and material size and if all is well hit the go button.