Lost Z axis

[Vistacarve]

Hi all it's been a while since I have had to ask for help on this forum.
I have a home built router table with a Xylotex three axis kit that includes XS-3525/8S-3 stepper drive board, 3 x 269 oz in steppers and power supply.(Running Mach 3 as an operating system of course)

I have been running this set up for just on one year and now, just as I am  starting to get some good paying jobs it has let me down.
For some unknown reason the Z axis (although working perfectly on screen) has decided it will not move up or down. when attempting to jog the Z axis the stepper motor just makes a low buzz or hum but won't actually move.
I have checked all of what I think are the obvious things and by process of elimination have come to the following conclusions.

Z stepper motor works fine (tested by swapping Z and Y motors)

All wiring and connections appear to be correct

Stepper drive board replaced with new one (this just made matters worse, all three stepper motors would hum but not move) Put original drive board back.

All computer leads and connections checked.

I am finding this so strange as everything was running fine on the last job I cut and I have changed nothing since.

If anyone can offer a solution or suggestions I may try before I get buried under the work that is piling up I would be most grateful.

Many thanks

Lawrie
Vistacarve

[Hood]

To me it sounds like your driver is bad. I know you swapped out with another and the problem got worse but that just makes me suspect that it is also bad. The way I would go  is to swap out the Z drive for the Y and see if the problem follows the drive. I realise that the drives are combined on one board but you can still set pins within Mach to reflect the changes. If you use the Y pins for your Z axis then if it still doesnt work then you know it has to be the board. To confirm set up the Y with the pins you have asigned to the Z, the Y should still work if its a drive problem.
Hood

[Vistacarve]

Thanks for the assistance Hood and yes it does appear to be the drive board that is the problem.

As to the new replacement board also being a dud, I went back and read all the info sheets that came with the board again and discovered the following.

Unlike the first board which was factory set to suit the stepper motors I purchased with it, this one comes with the Vref Voltages set to zero and the board will not operate until these are reset to the required 3.35v.

The instructions given areas follows:

Adjust your Vrefs at TPX, TPY, TPZ.....(Black lead to GND, Red to TPX) Turn Potentiometer counterclockwise for +.
Do not adjust Vref voltages with motors attached or to voltages higher than 3.60v.

Being for the most part a "plug and play man" I suddenly realised how little I really know about this stuff. I know what a potentiometer does but not a clue as to what it looks like, where to find it on this board, or how to go about testing and adjusting it or them to the correct voltages.

If you or anyone else could assist me with some detailed instructions on how to go about this task without creating lots of expensive smoke then I think I may be heading in the right direction.

Many thanks
Lawrie

[Hood]

Well from what you have written it seems you will need a voltmeter. You will connect the neg lead (Black) to a ground on the board and the positive (red) to TPX. then onto TPY and then Z. TP will stand for Test Point and you would see them printed on the board somewhere. Then you will turn the pot, which most likely will be a trimmer pot so you will need a small screwdriver. You should see the voltage increase as you adjust the pot. It says with no motors connected so make sure you dont, however you will need your power going to the board.
 I will go see if I can find the manual and may be able to see where the pots and test points are located.
Hood

[Hood]

OK just had a look, you should see the pots for each axis in the middle of the board. You will see a capacitor and next to it a pot, then another capacitor and another pot and then same again for last axis. The test points ofr each axis are just below. Find out what current your motors are then look at the table on page 2 of the manual and adjust until you see the voltage specified for that current. Move onto the next axis and so on.
 If you are still not sure just ask away.
Hood

[Vistacarve]

Hood

Once again I thank you for your assistance. I can now go and set the Vref voltages and run some tests before hopefully being able to get cutting again.
I will post and let you know how I got on.

Lawrie
Vistacarve

[Hood]

No probs.
Hood

[Vistacarve]

All went well and everything is now operating as it should. 

Boy am I glad I have this forum to call on when things go wrong.

Now it is full throttle in the workshop to get these orders out on time.

[Hood]

Excellent news.

Hood