Marantz SC-80 Pre-Amp: Source for Parts?

[eThink]

Looking for Balance Control: Part # RM01041310
and On-Off Switch: Part # SP01011620

Used with Marantz SC-80 Preamp.
Made in Japan 1990-93.
According to Marantz America, the part is no longer available.

Looking for an alternate source.
Is this a "standard" part available from other sources?

Please help.

Thanks,