machine very nice to work with. Now It problems me a lot, with the thread breaking, the thread starts to get struck and then breaking. What is the tension to be adjusted.

Thread your machine with a different thread, If that works nice, then you can say for sure that it is the thread that is the problem.
A new needle sorts a lot of thread problems too.
From Bev

Hi Bernadette, I don't have a Janome, but just in general it could be a few things. Others might can add to the list. LOL... Have you looked at your manual and followed the instructions for that? Is your spool possibly catching on something? Is your needle new? Have you adjusted the tension? If tension is too tight, the thread will break. Is your bobbin in correctly. These are just a few ideas to look for. And it could possibly be your thread might just be old. It's hard to say. Maybe someone else has other suggestions. :)