schuu6p,
First make sure the stop motion nob is tight ( the chrome one inside the hand wheel ), and the bobbin winder nob pushed to the left.
If that doesn't make the needle bar move up and down then you'll need to remove the face plate and make sure nothing inside is broken or come loose.
You can straight stitch without the cam in place, but if you move the needle position lever it will crunch the needle. The cam in place is the only thing that keeps the needle within it's limited travels.
When you lift the trap door there should be a chrome nob about 1" in diameter on top of the cam drive. If not you'll need one of those too. And the ZZ cam you need is a #1.
There are 30+ flat cams you can use in that machine so any cam can set on the cam drive to keep the needle safe.
Also, since the 338 is an all metal machine it is worth the effort to get it working and procure the cams. It's a good simple machine that works.
Joe
Last edited by J Miller; 11-21-2012 at 06:01 AM.