Explorer Problem with X axis

[Gary Hair]

I am having a problem with my Explorer ZX and I am hoping someone might be able to help. I have had this laser for almost 5 years and have had virtually no problems, until today... I am running a large job and the x axis is shifting. The piece is 32" x 40" and I'm lasering 26" x 39.95". I am running the top of the engraving on 5 pieces of material then I was going to run the bottom half. The top all worked fine and the first bottom worked fine. On the second bottom the x axis started drifting, the image started skewing to the left as if the 0,0 was moving left. I stopped immediately and started cleaning, this job was really making a mess of things and I thought that might be the problem. I have cleaned the lens and mirrors after each half but the rest of the laser was pretty dusty, so I cleaned it really well. I turned off the laser, reseated all of the connections to the x motor, at the motor and on the main board. I reseated the memory module and all other connections on the main board. Everything is moving smoothly, no different than it has been for 4-1/2 years. When I turned it back on and ran the file again, with the lid open so the laser wouldn't fire, I could watch the red dot slowly creep left. After about 45 seconds of running I stopped the job and manually moved the red dot to 0,0 - the readout showed it to be at 1.75" x and 0 y, even though it should have been 0,0.

I have tried everything I can think of but I'm hoping someone has the "magic" cure. Of course, I have about 20 hours of lasering to do by Friday and my laser is down...

Thanks for any help you can provide.

Gary

P.S. I PM'd Rodne with the same info but thought I'd post here as well.

[Gary Hair]

Update:
As a last ditch effort I figured out how to remove the cover over the encoder and lo and behold, it was filthy inside! I was certain, until tonight, that the encoder being on the shaft of the servo and well protected, that I wouldn't have to worry about it getting dirty - boy was I wrong! I don't know how long it's been getting bad but I'm sure the job I was running today was the proverbial "straw". Anyway, I cleaned it off and everything is fine!!!!!!! I never thought that I knew everything about my laser, but the one thing I "knew" was that the encoder was protected. I hadn't learned anything else yet today so I was due.
Gary

[Robert Walters]

Gary and anyone else,

If you get random movements or "jitters" and your system has servo motors,
that's a sign that the encoder is confused and can't find it's location so the motor is trying to compensate.

Be it dirty encoder (as in Gary's case), loose cable, etc.

[Mike Null]

Gary

Glad to hear of your "good luck". You could have been down for days.

A very good post to share.

[Rodne Gold]

Wrap the cover and all seams/openings in masking tape , you will never have the problem again.

[Gary Hair]

Rodney,
It looked like it was sealed pretty well but I'll make sure it's dust-proof now.

Thanks,
Gary

[oscar martinez]

As I mention before some times the encoder colects dust, Very fine dust . cleaning the encoder solves this kind of problem.
Atte Oscar.
From golden state.