My janome mb4 won'tt open designs I send from my computer. I have had machine for a year and never had this problem

Try page 24, although it may be referring to something else. Such information like hours used is only available to a technician using factory computer software.

https://www.janome.com/siteassets/support/manuals/embroidery-models/inst-book-mb-4en.pdf

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I`m confused whether you mean top bobbin or lower bobbin...You can go back to the point where it broke...Brother machines are far more simple when this happens...

This may prove helpful...
http://dlbargainbox.com/index.php?main_page=product_info&cPath=1&products_id=217

could be a computer problem, needs to be serviced

Repairing a Janome or New Home Sewing Machine ...

www.thriftyfun.com/Repairing-a-Janome-or-New-Home-Sewing-Machin...

Question: Memory Craft Machine Won't Run ... I'm a computer repair technician and good with tools, is this something I could fix or should we .... machine which will zig zag fine if i turn the wheel by hand or sew very slowly; as soon as I speed ...

Janome won t turn Sewing Machines Questions & Answers ...

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Janome sewing machines won t turn related questions and answers. ... Ad. Question about Memorycraft 6500P Computerized Sewing Machine ... it could be a part has worn or broken, esecially when the hand wheel won't turn,, it needs to be.

Janome wheel not turning Sewing Machines Questions ...

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Janome sewing machines wheel not turning related questions and answers. ... 10000 janome jamming fly wheel won't turn fly wheel won't turn warning for too thick ...the hand wheel is not moving the needle at all Hi I was unable to move the needle at all ... Janome Memory Craft 9000 Computerized Sewing Machine.

Change your needle and if it continues to happen, change the thread. Most likely your needle and thread are not compatible, ie the thread is too large for the needle's eye. Also, inexpensive thread will shred.

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If your embroidery is distorted be sure you are using the right stabilizer for the fabric you are doing the embroidery on and enough for the density of the design.

I hope that helps.

This is usually caused by the y axis movement system. Occasionally this system can come out of sync, and cause the issue you described. Your y axis pulse motor may be going bad as well. In either case it would be best to take your machine to a Janome dealer for repair.

It sounds like your x-axis sensor is either broken or malfunctioning. When the machine initializes, this sensor tells the machine when it has reached the furthest point in it's range of motion. If it is not working properly, the carriage will extend past it's normal range, and stop when it physically cannot move any further. After a specified amount of time the x-axis motor shuts off, and an error message will appear. For a certain diagnosis and repair, it would be best to take your machine in to a Janome dealer.

checks that the strip wire and strip wire sensor, this worked well.
(the strip threads is the small spring by which you spend the thread to thread)