Need help reassembling a Sonora

[gramophoneshane]

I'm assumimg as you haven't pulled the motor down, it needs to have all the old lubrication removed & replaced, especially the grease in the spring barrels. The grease in the barrels will dry up over time, and prevent the motor operating properly due to friction.
Also you need to make sure the tonearm moves freely in all directions and is lubricated.
Once that's all done, if you are still having problems, you may need to look at replacement main springs because they can get tied if they've had a lot of use.
Once operating properly, those motors shouldn't have any problem playing a 10" record from any era, provided the disc is in reasonable condition & a new steel needle is used every time.

[alang]

Thanks Andreas - I have gotten it (almost) back together, and so far every thing works. The url that was referenced did not show up, or I did not know where to look for it.

Well, looking back at my response, I guess I forgot to add the url, sorry
Here is a link to the Sonora manual: http://nipperhead.com/old/sonora.htm

Regarding the slow down, besides trying a different record I would also try a new "soft tone" needle. I noticed that some later 78s slow down and don't play on "loud tone" needles. If both does not help I would start the project to clean and lubricate the main springs.
Good luck
Andreas