ESA26523 5-way switch for vintage Technics SU-A6 preamp

is it part of the preamp?

perhaps just buy the pre-amp.

1 day left
http://yahoo.aleado.com/lot?auctionID=c851747485

aledo, you must make an account, and deposit money in your account first. then they buy for you, they get it, ship it to you.

Bill bought his JVC tonearm on buyee, Yahoo Japan, similar, same unit listed there

https://buyee.jp/item/yahoo/auction/n451080613?conversionType=search_suggest

Japanese listings/translations are tricky

if it says 'Junk', perhaps for parts, or, sometimes that only means they have not tested it, or ..., always good to read the full description

That switch is fairly common, regarding it’s use in the manufacturing era or window of time. It might be used in a hundred other devices, in that same pin configuration.

eBay is your friend, in this case. As well as google image search.

You’ve got some work ahead of you, to get this done. I tend to take them apart and clean the contacts, but that is not for everyone. If it is just dirty contacts, that is.

Panasonic’s mod of the unit, involves a bit of conductive copper tape up top on the plastic part, to alleviate some last bits of electrical noise interference.

They probably did (adding the copper tape) it for the ability to boast about s/n ratios, as some people buy by the specifications sheet. And that people expect those numbers to be ’better’ in the more expensive gear, or in the newest pieces.. 

Actually, the copper tape is some end user's modification--from looking at pictures of the insides of the Technics units, on the web.  Luxman tended to do that right from the factory in some of their best gear, but they began that a few years later, in the late 80's and early 90's.