1987 to 1990, after which Philips regained the rights to the name for North America (which they already owned everywhere else).
The problem with that Wikipedia entry is that it makes no distinction between Marantz worldwide, Marantz Japan, and Marantz North America, all separate entities.
You'll find this much more accurate and thorough:
http://www.dutchaudioclassics.nl/marantz_the_man_and_the_company/
The period from 1980 to 1990 is sometimes referred to as "Marantz' Lost Decade" - for North America, anyway - due to the deterioration of the NA product line and then Dynascan's further descent into mediocrity. Meanwhile Marantz Japan and Philips continued to develop and market worthwhile components - some of which were sold in the USA as Philips brand.
All else aside, if that PM630 works, it's still likely worth $30, even if it is a Sanyo.
Cheers,
Larry B.