Ichigo,
How "vintage" is your Marantz tuner? Is it an analog model, with manual tuning? Is it vacuum-tube or solid-state? And if solid-state, does it have a digital readout with pre-sets?
If it has a manual tuner with a horizontal tuning dial and manual pointer, then J. Bellemare is correct. The pulley may be slipping and the pointer has become dislodged.
If it's a vacuum-tube model, then tubes drift all the time and deteriorate, and it wouldn't be worth having it realigned unless you simply like the idea of a retro analog tuner.
In theory, digital tuners should not go out of alignment, although I owned one in the early 1980s that did malfunction.
One other factor: the FM band in Japan is different than in North America, but such a degree of error that you cite would not occur.
Regards,
Alan
