some tight stitches on some needles

[Elena_m]

hi,
few days ago started problem on some needles stitches are not normal, some of them on very regular intervals are very tight. see foto, please. on one needle i replaced red thread feeder and thread feeder roller for new ones, but with no result. it started in first day 3 needles, next day other 4 needles. now i have only 6 needles working normally, i mean making good stitches. what is the problem?
thanks
Elena

[Wishes]

Sounds like the color change gear in the back of the feed rollers has a crack in it. This will cause irregular stitches and will continue to get worse as the crack gets larger.
Good luck.

[Mama Kass]

Here is some good advice from Rod and Sharon to get your diagnosis started:

"The right upper color change motor cover can be removed to check the condition of the main threadfeed drive gear. It is a white nylon gear approximately 1.5" in diameter. If this gear is broken or fractured it will cause the gear to wobble resulting in gear slippage,for lack of a better definition, which in turn will cause all kinds of grief. Eratic sewing, loose loopy stitching, false or real bobbin and thread breaks, etc.. If it is fractured or broken, it will need to be replaced.

I have often seen lots of thread get wrapped up in these gears which will cause them to fail....it is mainly a maintenance issue..

In "Maintenance", "Steppers", you can go to the far right hand column labled "Threadfeed", click on "Home". This puts the threadfeed drive motor back at a preset home position. But, unless you check for any thread buildup in the total threadfeed drive gearing system, which could cause drag and failure, then this will not help.

Look at the instruction I mentioned before for Debbie in my last post....that is the first step. Removing the threadfeed rollers and looking down in the pockets with a flashlight to make sure one of these gears are not broken and/or there is thread buildup around the shaft would be another step."

[Elena_m]

thanks for reply, i analysed and realised that color change gear in the back seams to be not OK. his movement is not round, it makes like 8 and on full round movement not all teeth of gear are getting in contact with thread feeder roller. I have spare gear, can i replace it by myself or i need to call Melco technician?
thanks

[Rod or Sharon]

That is the main thread feed drive gear, not the color change gear. To replace it Melco sells a small T handed wrench to help take the axle stud out of the casting. Short of that it is difficult to get the damaged gear off of the shaft and get another on with out messing something up,

Also there is a small "C " clip that holds the gear in place and also a very thin thrust washer behind te C clip. The motor can be removed from in front of the gear, but it must be done very carefully so as no to damage the optical sensor laser it goes thru....

Rod Springer
Amaya Tech & Trainer