475 Vertical AC/DC Coupling switch

montanaaardvark <blombardi@cfl.rr.com> <blombardi@...>


I just joined this group and did a search of the archives for some
info. Couldn't find anything on my problem.

A couple of months ago, I bought a 475 from someone on eBay. The
scope basically works fine. I haven't done a full calibration, but I
can check horizontal accuracy with a signal generator and that looks
good, check voltages with a few sources I trust and they look good,
and other overall checks.

It has one problem - both vertical channel coupling switches, the
slide switches that choose AC or DC coupling, or ground - are barely
working. While the switches on all the 475s I've used over the years
at various jobs "snapped" into place, these kind of "mush" into place.
Basically, I could get one channel into DC mode while the other is in
AC mode. The scope is usable, but I sure would like it better if I
could get some better switches in there.

I've gotten a reprint of the manual from W7FG, but don't really see
how accessible these switches are, or how rebuildable they are. Can
anyone advise me on this? Is the only source of parts another old 4X5
series scope? Is this something it's best to send out to get fixed?


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