Ortofon cartridges are excellent, but there are no Ortofon conical options in P-Mount. I play a lot of 45 singles, and no ellipticals or line contacts will do for styrene anything. I now have a Broadcast E and several Ortofon OM compatible conical styli options on my 1/2" setup. But not knocking P-Mount if your LP collection is post 1970. It is good for fumble fingered LP users who meet that criteria. I love Ortofons.
You should check the date on the thread. . .You might also think about upgrading the stylus of the 92. I am running N104e on mine. Big improvement in a bunch of ways.
Can't say for sure on the M3, but all the Technics p-mount era decks that I've seen use a fairly standard AC cable, similar to this one.
Yes, it is the standard oval two-prong power plug, same as some other Technics and Sony gear I have. This is the original Technics cable, pulled out of the back of my M3. It is labelled 7A 125V.
The plug face is 15mm by 8mm. Plugs dimpled in on the sides will work, but some variations that are flat on one end will not. Chances are, you have something else around the house with a power cable that will work.
Nice taste in music BTW...