I'm not sure how popular Singer 900 sewing machines are. Looking at this one, it seems to be very well built, with typical Singer quality in many places (but then there are other places that are lacking a bit). When I first plugged this one in and fired it up, it growled. Wow. What a noise. I'm thinking it is because it has an electronic motor control and running at slow speed seems to make the various parts vibrate loudly. However, once I oiled it up, the growling subsided substantially. It is now a fine running machine.
If you look in the very center of this next photo, you'll see a part I had to make that was keeping this thing from running well. You can see there's a large screw head holding a grey plastic piece on the main cross shaft. There was a white plastic bushing there that had split. The bushing takes up the main shaft end play so it doesn't dance from side to side when it runs. With no bushing, the shaft will slide side to side when the cam gear system puts pressure on the shaft. I was able to make a new bushing out of a piece of grey PVC pipe. I cut a section of pipe and heated it with a heat gun so I could form its ID to the required 3/8" diameter of the shaft. A little touch-up on the grinder and a slot in the top for the screw, and we're good to go. I think they make a replacement part for this but I wanted to see if the pipe option would work.
The cam stack and stitch selector system looks somewhat similar to a Singer 401 system, but moved to the right side of the machine. The add-on cams are reversible, having four levels of cam peaks/valley per cam.
The underside of the machine is nothing to write home about. Plastic/nylon gears for the rotary hook/bobbin winder system and feed dogs.
Belt drive for the lower shaft, and electronic motor control.
The 'Finishing' person didn't get their own rubber stamp so they had to hand-write it in... and they messed up. :-( Maybe they got a stamp one day. And the packing person wasn't too concerned about placement and orientation.
Now here's something odd. When I first saw this needle plate (below), I thought the feed dogs had been so loose, they chattered about and caused all this mayhem. I then realized that someone had replaced the rubber feed dogs with steel ones that didn't fit the plate, so they took a dremel (or whatever) to the plate so it would fit.
I think they were a little more aggressive than they needed to be. I might have to find me another needle plate for this machine.
It's alive! It works! There's cute little doggies and waves and flowers that can be made. Ok, so the doggies are a little on the ragged side. The flowers look pretty good though. Maybe it's the denim fabric I used...