Z-axis 248 on startup problems

[packerguy]

I am trying to do a carving today and i am getting a z-axis 248 error message when it first starts to home.

It has a new style z axis motor. I cleaned everything as well as i could. I did notice that when you go into the sensor checks and if you move it in the "y" axis the number will change but if you move it up and down it stays at zero.

I checked to make sure all the connections were tight, do i need a new ribbon cable maybe?

Last time i used it about 3 weeks ago it worked great.

[mabco12]

It looks like time to get that new ribbon cable!! Double check all connections because I had the same problem after swapping the z bundle servo motor and ribbon cable but had a connection backwards so it would not home or do anything but give the z-stall prompt.

[packerguy]

Now when it starts to home, it goes up all the way like normal, but when it gets to the top it stops and makes a loud grinding noise, then after about 3-4 seconds it says "homing problem: z axis".

When you move the head up and down by hand the z-axis sensor does go up and down now???

Any ideas???? I dont see anything that is blocking and or in the way.

[Digitalwoodshop]

Good News Bad News.... Bet the problem was a loose plug in the Z Motor to the Circuit board next to the Z. Or a loose flat cable that may have gotten pulled at an angle while under power and shorted something.

The fact that it drives up and makes noise before faulting is a bad thing....

Try this.... Move the head to the lower position and try it again. It should move up to the top and then Y moves left and right and left.

If it drives up fast into the top stop then either the motor is bad, a open wire in the motor causing a unbalanced electrical condition, driving only one way OR a shorted driver in the control computer caused be running the unit with a unplugged motor.

SO bad motor or bad controller.... Very Expensive..... OR like said above, the flat cable has a broken wire in it.

Good Luck,


AL

[packerguy]

how much play should there be in the z axis motor. It seems a bit loose.

I took the top off to get in there to see if i can get this fixed today. I have a job due that i need it for :-(

[liquidguitars]

you could check the screws..

Pull the Z pack and check the two screw holding the motor to the base assembly.

LG

[TerryT]

Don't know if this will help but.....
I replaced the z bundle about 200 hours or so ago. The black plastic retainer that holds the FFC cable into the board on the z motor came loose and nicked the FFC cable at the top. No problem for a couple hundred hours of carving. Yesterday the z axis just froze. I found that the inside bearing on the big drive gear turned into a wad of steel wool. It must have been due to the belt tension set too tight. I took it apart and replaced the bearings from an old Y motor that I had. I put it all back together and tested it. The z axis dove straight down and jammed. I checked around and noticed the FFC cable had broken one contact, the top one that had been nicked before. I was able to scrape the coating away and solder the wire together so I could finish the project.

So the moral is.... Check the bearings on the belt drive gear and make sure the FFC cable is in good condition.

[Digitalwoodshop]

I failed to replace that FSC Cable plastic holder one time and the cable DROOPED and snagged something and ripped it out while it was carving... Shorted out a motor.... I had extra motors and swapped it out and it worked.... So always replace the plastic retainer on the top as it supports the weight of the cable. A Drooping cable can snag.....

AL

[packerguy]

This machine shouldnt be this silly to use.

Thanks for all the ideas.

How do you remove the z axis motor? I got it to work up till it finds the surface and it would go thru all of it and then say the surface didnt match or something like that.

Im about to toss this in the trash. Really angry this is not working today.

[packerguy]

well i got the moter housing and motor off....the 2 screws that hold the motor to the plate that the 2 gears touch (dont know what to call it) were loose by at least 3 turns so you could touch the motor and make the gears not touch.

Im going to put it back together and see if it works.

[packerguy]

that seemed to fix it.

Anyone ever heard of that happening?

[liquidguitars]

yes. that why I told ya to look at it.:mrgreen:

LG

[Digitalwoodshop]

This machine takes patience to master.... A Short Fuse and it's not for you. There is so much to read and learn. Reading Tips and Tricks is a MUST.

AL

[packerguy]

yes. that why I told ya to look at it.:mrgreen:

LG

Oops.

Sorry, i missed your post. ;)