You will find lots of info on this machine if you look for its twins, the Janome Threadbanger TB-12, or the Janome HD1000 (current edition), L-344, and even a few others. This is a very nice machine, simple but all metal and reliable. I got one used for my sister and was loathe to give it up!
Do a search on patternreview forums for threadbanger and I believe you will find plenty of help...