I found out about another record changer that played both sides of the records.
It is the Thorens CD-50, and it is a drop changer. Here is a photo:
This changer has a push-type spindle similar to the spindle on a Collaro/Magnavox changers made after 1962, with a balancing disk on top, similar to the one on the PE-Rex A. But this whole spindle and disk assembly rotates for playing the bottom sides. The pickup head in the arm turns upside down to play the bottom sides.
I have not been able to find out if it has a one-side mode. There is a slide switch next to the tonearm rest position, but I do not know what it does.
Here is a YouTube video of one in operation:
http://www.youtube.com/watch?v=vgsloOKK-EY
That makes 8 different designs for two-side record changers I have come across (excluding jukeboxes):
1927-1928 - 2-Side HMV Automatic Change Gramophone - plays manual and slide sequences - 2 turntables
1929-1949 - Capehart Turnover - plays manual and slide sequences - record basket and ring
1935-1957 - Lincoln 30 and 50 - plays manual and drop sequences - record carrier and inverting turntable
1938 - Garrard RC-100 - plays manual and drop sequences - Segmented spindle, ejector arm inverts record
1941 - RCA Two-Side Magic Brain - plays manual and drop sequences - forked tonearm, no long spindle
1941-1946 - Thorens CD-50 - plays manual sequence - inverting headshell, spindle turns stack
1946-1954 - Markel 70, 71, 72, 73, 74, 75 - plays manual and drop sequences - wheels rolling on turntable
1962-1966 - Fisher Lincoln 60, 70 - plays manual and slide sequences - record carrying inverting turntable
Only the Markel 72, 73, 74, and 75, the Lincoln 50, and the Fisher Lincolns could play 33 and 45. A late version of the Capehart could play 33. All of the rest of these played only 78 rpm records.
