Need help identifying late 40s - early 50s phonograph

Can anyone help me identify this old phonograph? Supposedly it was my grandmother's and she passed away in 1948. I suspect that may be bad info, it may be early 50s, but I was born in 1960 and it's been in the family as long as I can recall.

There was a label on the bottom, long gone, but I could swear it was an RCA Victor. The turntable (changer) played 78, 45, and 33. The changer and speed buttons were ganged on top of one another, the small center button turned the unit on and off, plus reject, while the outer ring controlled the speed. The turntable was replaced about 10 years ago with a period correct one that looked identical except the changer arm was intact (my father, for reasons unknown, had the changer arm removed in the early 60s).

The pic shows the knobs on the side. Note the rounded front. I believe the cabinet is mahogany. It has two speakers but it's obviously not stereo.

I drug it out from under the workbench a month or so ago and it grudgingly fired up, but no signal. The cartridge must be bad, as I can get a signal by touching the cartridge's wires.

I didn't access the tubes but I can tell you they are the small type I'd normally associate with 50s and later, the size like a 50C5 or 12AX7.

If anyone thinks they can come close with a model and/or date, I can supply better pics, this was just an impulse, finding this board. I've got a bunch of 78s I'd like to play.

1950 is the first year real 3-speed record changers appeared, and some of them were rather strange in the way they were set up. The changer you mention probably came from 1951 or later.

1948 and earlier had only the 78 rpm changer. 1949 had two speed changers. Some late 1949 units had a spring you could put on the motor shaft to get manual operation at 45 rpm (they didn't know how to play the 7'' size).

What you describe is probably a V-M record changer. Shortly after they were introduced, they became ubiquitous, adopted by many companies that formerly made their own record changers. Here are links to photos of their products.

http://thevoiceofmusic.com/pp.htm Has the dates of introduction!
http://www.radiophile.com/vm920.htm

One interesting photo on the first site is the one for the V-M 950. This original manufacturer's brochure shows the machine loaded with and playing a stack it can't play. No V-M changers before 1966 could mix the 7'' size with other sizes. It couldn't mix speeds either (the top record is a 45, and there were no other sizes for 45 in the 1950s). On the next change cycle, that changer would set the arm on the 10'' record under the 7s.

Overexuberant marketing department? Thorens did the same thing with its CD-43.

Webcor used a single knob which was pushed down to reject, and rotated to change speed, or a pushbutton with a lever moving around it.. Philco, GE, Garrard, and Motorola used a side shelf in the early 1950s, not an overarm.

That looks like a Zenith or Admiral cabinet. But those companies used their own record changers until around 1954 or 1955, and their changers didn't have concentric knobs.