[vdude]

Z rapid up and down (fast)with a 409 error.Encoder bad?
Thanks

[One of Many]

What model?

Will it home?

Is this is one with the SEM DC servo motors? If so, it may be as simple as the Z tach needing cleaned or a brush replacement by capable personell.

DC

[vdude]

this is a 96 vm-24 cent. 5 controll.i turned home spped down to 20 ipm and it will now home out but any rapid move in z throws the 409 error.where would the z tach be located so i can check that?

[One of Many]

Kill the power, then;

It sounds like the Z SEM DC motor tach issue so..... The motor rear cap needs opened to remove the encoder mount. Mark the cap, encoder mount position on the outside relative to the motor body. There are a lot of holes in the rear face of the motor and things can easily get misaligned on reassembly. Mark it so you know how it should go back correctly.

The encoder mount is a cast cage that is between the cap and motor body. There is a small white plastic coupler(.5" diameter x .25" thick) with slots in it that is between the motor shaft and encoder shaft. When removing the encoder, make sure it does not get lost. Normally it stays on the encoder, but be aware.

Once the encoder is set out of the way. The tach brush plate is a phenolic disk with the brushes face down. Mark its position inside and carefully remove it. Then you can inspect the brush assembly.

I have removed some Z servos for this procedure, but.....you might be able to clean it in place if you can stuff paper towels down in there to absorb the flushed gunk. Removing the motor involves a lot since the head needs supported and then getting it back together may alter the homing position slightly. The issue here is between the belt position and encoder marker pulse might not end up in the same place relative to the homing switch.This would be in prep to flush the tach with contact cleaner or brake cleaner so the carbon dust/sludge doesn't run down to the motor brushes etc. Use a tooth brush and verify between the poles are clean and the brushes are still long enough to make contact.

Putting it all back together, be very careful with the brushes. When putting the tach plate back in you MUST push the brushes out as they slide back onto the commutator.


You can buy the brushes from Milltronics or Clarkson may sell you some.

Or send the motor to Clarkson as a core or repair and purchase a re-man'd motor if they have one ready.

Let me know if you need further details.

DC