Big, BIG tangential turntable of the sonically successful kind.
Produced in rather sizeable amounts, contrarily to what might one believe and the original 180,000¥ list price: like the smaller PX-3 (135,000¥), there are plenty of PX-2s around.
The original PX-1 mammoth gave way to more acceptable designs, but still filled with sensors of all kinds to properly keep the tangential tonearm... tangential to the record groove - electronica here we come ! The path opened first by Sony and the PS-B80 in 1977/78 was quickly followed by many, for our auditive pleasure.

I only know of another tangential turntable sonically as fully satisfying as the PX-2: Sony's PS-X800. The latter had somewhat gimmicky looks which probably kept it from becoming a serious "audiophile" seller while the former had stark, dark (too dark) "serious audiophile" looks written all over itself. Make it a darker grey à la TA-N86B and I'm in.

Yamaha's PX series was built by Micro Seiki and I believe partly engineered by same as well. Only Sony, Matsushita and Victor had enough clout to sustain in-house LP player development - the others had to have someone helping them in one way or another. The base of the PX-2 and PX-3 is BMC btw : Bulk Mold Compound, as in SBMC (Sony BMC :).

Excellent vinyl players at any rate, worth their reputation.

Check K. Nisi's page dedicated to the smaller one: PX-3.
Check freakbeatfreak.com to see one.
Check the EURAS database for a tech tip.
Check this page for a PX-2 in the studio.

...(more technical meat here at a later date)...