Hi Linda,
I had one of these machines many years ago. I will answer as far as I can remember. This model is now about 35 years old.
There is no sponge bar in the trip bar, it had a type of cloth covering.
The buttons on the carriage should stay in until you cancel them but not all of them at once! You have two for partial knitting (slip) and two for tuck - one for each direction of knitting. It was possible to have either both tuck, both part or one of each. I can't remember what the fifth button was for!
The problem with the needles not showing the pattern sounds to me to be a problem within the needlebed. There are a series of very fine plates which have to do with needle selection and over time they stop working. As frustrating as it sounds you might be limited to stocking stitch or hand selected patterns.
Sorry I can't give a more encouraging answer.
Regards,
Sue
April 2013