osewme

I'm not sure if I've posted this in the right section but moderator can move if it's incorrect.
I have a Janome Magnolia 7330 machine that I purchased new in Sept. 2009. Less than a year after I purchased the machine I started having problems with the machine. I would stop sewing (take my foot off the foot pedal) and my machine would keep sewing. Sometimes it would just start up on it's own. Sometimes it would sew very slow & sometimes it would take off like a rocket without me ever touching the foot pedal. I took it in for warranty to an authorized Janome service tech. & he said the foot pedal was faulty & he replaced it with a Model YC-485EC-1 foot controller. It cost $75 to replace the pedal (I got reimbursed because it was under warranty). All went well until about a year ago. Now my machine does not always start after I push the foot controller. Sometimes I have to "tap" it several times before it starts. I've tried blowing canned air inside but have not actually taken it apart for fear of making things worse. Any suggestions as to how to fix this problem without having to spend $75 for a replacement. There are no screws on the outside of the pedal for me to take it apart. How do you get something like this apart? Here's a picture of what I have. Thanks for any help on this.