Electronics from the late 1960s to 1980s from major manufacturers like Mitsubishi, Marantz, Sansui, Pioneer, etc. are not only very reliable because of build and parts quality, but also because of the state of the art in design which I will explain further below. That said, tuners and tape decks are not as reliable as amplification product due to their mechanical nature of operation. The only real issue with vintage electronics is the power amplifier. If it becomes defective, finding a replacement may be difficult requiring someone with experience and expertise in servicing vintage electronics to either find a new replacement that matches specifications or a used part. Also, with vintage equipment, bulbs or CAPS may need replacement and the tuner may need alignment.
The state of the art for circuit board design and manufacturing back then was manual surface mount through hole technology where components are hard wired and soldered. Components were larger. Today, printed circuit boards use surface mount technology (solder directly to the board surface) with much smaller components. Most components are machine mounted, and only a minority are manually mounted. Repair becomes difficult often requiring mounting new components under a microscope and by someone with keen expertise. If direct replacement components are not available, matching alternatives becomes more difficult since today’s equipment has software that may be affected. Often, the whole board may need replacement even if one component is the root cause. If that model is no longer supported or the manufacturer is out of business, it may be impossible to repair. Therefore, vintage equipment is easier repair IMHO. It will be interesting to see, and at my age I will not see it, if today’s designs will be making music 50+ years from now
I have my farther’s Pioneer SX 828 still making music since the 1970s. Completely original including bulbs Just occasional contact cleaning.
If you proceed, find a good vintage repair service and have the tuner alignment checked and a general check and cleaning. It’s worth the effort and cost.