I picked up this 99 recently (before I found the 201) on CL. It was the cheapest and closest to my house so I bought it. The slide plate was missing but the machine did work. The wiring is not original and has been rewired and looked good. There was no rust and didn't need too much cleaning at all. An easy first project for 30 bucks. I do not have before pictures. I know better now.
Once I got it home I found some other problems when actually trying to sew on it. The machine wobbled when sewing. Upon closer inspection I found the reason for the wobbling. In the right hand corner one of the pieces of wood inside the case was missing. I cut a piece of wood and glued it to the corner and stopped the wobbling.
Another problem was the tension. I could not get the top thread to eliminate the loops. I made it worse when I tried to adjust the it and couldn't get it right no matter which way I turned. Took it apart and found the spring smashed and twisted way inside. I had to pull with pliers and then go in with a small pair of cutters to cut the rest of the spring that was stuck inside.
The third problem I had was the bobbin winder. Decided to take it apart to clean and when doing so I found it had been put together incorrectly. Also found the spring that keeps the winder up when sewing was missing. I was able to get the nut off the back of the wheel but could not get the screw out. Let it soak for two days and still nothing.
So I cleaned and put it back together with a new wheel but the winder would come down and hit the balance wheel. I think they may have intentionally put it together incorrectly to keep the wheel from coming down.
Here is what I did to solve the bobbin winder from coming down and staying in winder mode at least temporarily. I took a small paper clip and looking at the picture of the spring I wrapped the paper clip around a screwdriver and wrapped it around a few times. I used a small jewelery needle nose pliers to shape pin on each end. The first one I made was too small. I got something a little fatter and another paper clip. This one was a good fit. I screwed the bobbin winder back on and to my surprise it stays up. I was tickled pink.
I ordered a slide plate and tension spring from sew-classic. I have learned so much and I am not done yet. I haven't tackled the feed dogs and the bobbin case yet. Wanted to sew a little first in case I mess/break something.