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FWIW there's a balance between "cheap" and "not banging your head against the wall". Totally get not wanting to spend a ton on a first project before you even know if you'll stick with it, but going TOO cheap can be a self-fulfilling prophecy where the cheap parts make the build and end result miserable.

Where I 100% would NOT cut corners is the power supply for the steppers. Get a good one, ideally transformer-based (not DCDC/switch-mode). Steppers decelerating dump energy back into the PSU and can cause voltage spikes, especially with a DCDC supply with relatively small output caps (the transformer-based supplies already have large capacitors to keep the output relatively stable, so have fewer problems with this). If you do use a switch-mode supply, put a BIG capacitor on it, with a high voltage rating. I think I put a... 1000 uF/250V capacitor on mine after blowing up a driver board and a few "unkillable" GeckoDrive stepper drives. No issues after that.

Spending an extra $50 or something on a good PSU can save you hundreds in other killed electronics (not to mention time and sanity).

If absolutely nothing else, not getting the cheapest of the cheap-cheap no-name supplies is probably a good idea, just from a fire hazard perspective.

For circuit examination here the naked blue PCB. 
 

Ha, ich hab ne XS750.
 

I didn’t see that the instructions were changed. I’ll have a go at those on a new system. that one is being heavily used for testing now.

Such "diy cdi", das sind sehr einfach selb zu machen.
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Hab ein 50 yahre alte Yamaha XS500 in gutte zustand aber leider kein frei zeit, die cnc gescheft ist zum teufel geganen, muss zuryck mit PC's arbeiten und das gibt wenig geld.

An old PC with parallel port, cheap TB6600 drives (smaller ones with TB62s109 are good), and motors, that is all you need, probably under 100$ total.

Wow that just got expensive. This is a portable table, the cut dimensions are adjustable at the design stage and I am probably going to make mine 1000x800. The designer suggested a Nema 23 stepper kit with DM542 drivers and a Mach 3 controller from Aliexpress at about $235. I was hoping to use something like this probably with just a different break out board. Is this not possible? This is for hobby use and I am in QLD Australia if that makes any difference. This is also my first build, hopefully learn something and able to modify or make a MK2 at some stage.

Hallo zusammen,

wer kommt aus Deutschland und kann helfen?
Ich habe ein altes Motorrad 40jahre.
Das Motorrad hat eine elektronische Zündung die Probleme macht. Immer wieder fällt die Zündung aus.
Ich habe mir die Platine angesehen. Ursache sind brüchige und kalte Lötstellen.
Nun ich habe schon Ahnung vom löten, aber die Platine verhält sich merkwürdig.
Sobald ich einen lötpunkt erwärme zum nachlöten, fängt es an zu blubbern und die Lötstelle bekommt Löcher 
Nachgelötete Stellen brechen wieder auf.
Meine Idee ist, die Platine in ein Lötbad zu tauchen.
Vielleicht hat jemand so etwas oder eine Idee wie ich das Problem lösen kann?
 

Why make it so complicated?

Just use CN1.
Simply connect the home switch DI3 and COM pin 13 here. Use the wiring diagram on page 47 for the external power supply.
Use homing mode 4 or 6, depending on where your home switch is located.
If everything works and you have encoder cables with batteries, you can switch everything over to multiturn absolute encoders—which don’t require homing—by following the instructions above.

I wrote these instructions because there are issues with XYYZ (gantry) axes. 
Explanation:
During CIA402 homing, control and monitoring of the axes are taken away from LinuxCNC. The internal servo homing is triggered. You can only see the current position of the axes and how they are moving. Once the axes have found their home position and report that they are ready, control is returned to LinuxCNC. This results in several problems that can become dangerous!
1. After homing is complete, the axes may jump, leading to an error. This has already happened to you.

2. With gantry axes, there are synchronization issues. It can happen that one axis starts moving late or not at all. In the worst case, the gantry will be crooked or break.

3. Once homing has started, it cannot be interrupted.
Neither an emergency stop, a reset, nor disabling the enable signal will help. The servos will start moving on their own once they’re enabled again. The only solution is to turn the servos off and then back on!

Using LinuxCNC homing isn’t an option either.
The Z-index pulse isn’t output by the servos and isn’t available. Of course, you can also use LinuxCNC homing by moving to the home switch or limit switch the traditional way, but that’s imprecise and suitable only for a cheese cutter at best.

That’s why I wrote this guide.
Here are the steps again:
1. Get everything up and running. If you run into problems, there are many threads here that can help, or you can start a new thread.
2. Get CIA homing to work with the servos removed.
3. Convert the servos to multiturn absolute encoders following my instructions.
4. Install the servos and, on the gantry, make sure they don’t twist—otherwise your gantry will be crooked.

 

It also (i just discovered) omits the G43 after a tool change, which is likely to cause trouble.

This is rather annoying as G28 U0 is very much not a LinuxCNC style thing.
It's valid G-code but I don't imagine very many LinuxCNC lathes are using the U and W axes.

Yes, it seems to be the case. I seem to have better luck when deleting position file prior to opening linuxCNC and homing, it works without issue most of the times. The issue i had with the Z motor turned out to be a slight misunderstanding of the process on my side, i still don't have a z axis and I was simulating the homing switch hits triggering the sensor manually, but turns out the process needs the sensor to become hit again on the second pass before it'll attempt to look for the z pulse.

@andrax are you on an XYYZ machine like your posted config suggests? can you respond regarding how the Ys sync up with the absolute encoder? The other thing i'm concerned about is if I should use homing mode 20 instead of 4 for Y, because otherwise the z pulse step becomes something that'll mess up your parallelism without you being able to adjust by adjusting the sensor triggers

Regarding the post above:
Yes, you're right,
CIA homing isn't really well documented yet.

In principle, it works like this:
The CIA-home function triggers the servos' internal homing routine and monitors the status. Once the servos report completion, CIA-home signals to LinuxCNC that homing is finished.

The drive error after homing is normal.
This happens when CIA-home hands control back to LinuxCNC.
Make sure the lowest feed rate is set; the axes will then synchronize without errors.

For plasma and starting with LinuxCNC with stepper motors, I would get a Mesa 7i96s and a Mesa THCAD2 to read the torch voltage. Also get a Meanwell MDR-60-24 24 volt power supply for field power and a Meanwell MDR-10-5 5 volt power supply for logic. When you order your Mesa gear also get some of their DIN rail mounts and a couple of COMMX2 bus bars. That will set you up for a running start.

SoloRev wrote:

The issue seems to be DKMS failing with the latest debian kernel. I couldn’t figure out how to uninstall the kernel but I was able to stop it from being installed on a new system. Before you do a 

sudo apt upgrade. stop any kernel update with [code]sudo apt-mark hold *6.12* basically wildcard the 6.12 string on both sides to prevent anything related to the kernel from being updated. 

[/code]

Did you try the revised instructions in the first post?