Sounds like what a Voice of Music record player I was working on for someone was doing except that the tone arm wouldn't set down on the record it would just move around the tone arm rest and then set back down onto the tone arm rest and then shut off, and that was because the record player needed another record on the changer in order to activate/trigger the changer properly. your issue might be a slight variation of that issue. try it with another record the changer besides the one you are playing and see what happens.

A common issue on VM changers is shutting off beforre the last record plays., or shutting off when trying to play a single record. There is a delay tab on the slide that delays shutoff after the overarm drops down when the last record drops. That often gets sticky, and the the last record in the stack wont play. Any changer wont work reliably until you get ALL old hardened sticly lubicants out of it. With most changers you really cant clean them adequately without taking a lot of stuff apart.
Either that or your overam is bent so it sits too low.

The overarm (record stabilizer) was good on both units and all types of records, even stacked in multiples, consistently did the same thing.
What ultimately fixed it WAS tweaking the trip lever (lays on top of the slide) that fixed it:D.

Don't underestimate how many issues this thin piece of aluminum can cause when it is ever so slightly bent or gummed up as usual.
As the changer was operated repeatedly into the wee hours, I noticed how the slide and trip lever moved in unison as tonearm set down on the record lead-in groove. It was this movement that caused the tab on the trip lever to just catch the on-off lever when going by it.
Operating the working Motorola changer, I saw that the trip lever was bent down slightly at the end toward the power switch, so I did the same thing to this Philco.

This is not the end of this thread though, I have four more V-Ms to work on :sigh:

I recently spent some more time with the 2073:

The 10" & 12" sensors do work when they're held down by hand, but not during normal operation. The 10" sensor doesn't even touch the record because it's sunken too far from the top of the platter.

Tracking pressure is adjusted by a spring loaded clip that can be pressed into one of a series of slots on the underside of the tonearm. A pair of pliers are useful for repositioning it. The factory default pressure was 3.3 grams. I moved it to 4.3 grams for better results. Perhaps 5 or 6 grams would be best.

5-6 grams too heavy. 3.3 grams correct. Repair it properly and it will trip and work fine at that force.

depends on the cartridge. some cartridges need more to track without distortion. Zenith 2g cartridge was 2.5 to 3 grams, most ceramics needed 4-5, maybe 6, and the high output types and power point style ones needed to track at 8-10 grams. tracking force is related to the stiffness of the cartridge suspension. plus the friction of the arm bearings and trip mechanism need a certain minimum. most V changers need 4g or more to operate reliably, the Zenith 2G version has better bearings.