Epilog laser head slamming back & forth

[Brian Robison]

Hi gang,
I KNOW this has been discussed but I can't find it.
What causes the head to SLAM back and forth on start up?

[Bruce Volden]

MY TT did this a long time ago....cleaned the encoder/contrast reader and all was good.
This was my first dealings with encoder strip filth.

Bruce

[Keith Downing]

It's almost always the encoder strip or reader needing to be cleaned or replaced; or the ribbon cable leading to the reader. I've been told you can reverse the ribbon cable to buy yourself some time if that's the issue, though personally I couldn't get ours to read after reversing it.

It can (rarely) be the motor or even the motherboard.

I've battled this problem on our 24EX, it's the only real flaw I've found with the Epilogs from a generation ago (or as they get older?).

[Brian Robison]

I didn't have a problem until my x motor went bad, I replaced it and
my engraving started to wander to the left. So I cleaned the strip, no
luck. Replaced the ribbon cable, no luck. Cleaned the reader and then
my X started slamming back and forth on homing in.
I'll probably order a new reader and maybe a new encoder strip too.....
Just seemed odd to me....

[Kev Williams]

I'm wondering if it's a broken wire within the plastic drag-chain? I've had broken wires in TWO different machines, and the steppers go nutso when that happens... more later--

The thing about 'regular' stepper motors or servo steppers, is that while they're homing, they have no other instruction but to move one direction at a per-determined slow speed until they hit the limit switch(es). So a servo has no reason to use the encoder while homing. Once they hit the limit switch, the stepper now has a zero point and everything starts and ends there...

So, to troubleshoot this: While the stepper is homing, does it do the slamming/erratic/nutso behavior BEFORE it reaches the limit switch, or AFTER?

If BEFORE, then a broken or otherwise bad wire or connection could be to blame, as the motor will act erratic regardless of being homed yet or not-

If it goes nutso AFTER homing, then something is likely bad with the encoder, strip, or the circuitry they're connected to, since the motor worked okay until it zeroed out...

You might try checking wires in your chain, the one that runs along a Y rail, anywhere in the chain where it folds back...

This happened with my 'western' LS900...
406391406390

And this happened with my Chinese Triumph...
406392406393

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Checking and cleaning other plugs and connections can't hurt either- My GCC, which is my only machine with servo steppers, has never had a motor go bonkers, but it did one day started acting funny, and just slowly stop working... Had no idea what the problem was, but since wire connections have given me fits for 35 years, I decided to disconnect ALL connector plugs that I COULD disconnect, within the entire machine; they got pulled apart, both ends shot with electronics spray cleaner and re-connected. It was like a brand new machine after I got done. I've done that once since then for good measure, and actually, it's about due for another round :)

[Steven DeBusk]

I have a Legend 24EX 75W. Used, been fine until did some rotary work. head slamming to the back. took out rotary and cleaned optics, fixed the air nozzle, but not reading. Is the strip you are talkling about on the right side?? Steve

[Steve Clarkson]

No, it's a clear strip that runs along the x-beam. Depending on how much engraving you do, you should be cleaning the encoder strip every week or two. I would Google how to clean it and a few youtube videos will come up.