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December 23rd 04, 05:46 PM

John Miles wrote in
:

In article ,
. says...

Considering how longlasting and popular the 465 is,that's not a very
smart sentence.The same HF and LF cam switches were also used in the
high- performance 7000 series lab scopes.

True enough in the case of the 465. That model in particular seems to
have been very robust. You don't see many owners asking about how to
clean 465 switches.

485 switches, though, are another thing entirely. It's very rare to
see a 485 whose vertical attenuator switches aren't noisy. Perhaps
gold-pad abrasion has caught up to the instruments over time; however,
I'm personally aware of at least two anecdotal cases of noisy 485
switches being fixed (at least for the time being) with contact
cleaner.

It's possible there's more than one cause of switch degradation at
work in the 485 and other notorious "problem children." Either way,
though, the original designers were clearly not omniscient in all
cases, or the problems with certain models wouldn't be as widespread
as they are. I wish there were a sure-fire way to fix the 485's
front-end switches; it was my favorite Tek scope of the bunch
otherwise.

-- jm

Both 465 and 485 use the same HF cam switch contacts.

TEK used to have a repair kit that included both contacts,drill bits to
remove the securing rivets,and tiny nuts and bolts to secure the new
contacts.

They also had a repair kit for the LF contacts used in the timing
switch,with an alignment guide to get them straight.

Both are no longer available.
--
Jim Yanik
jyanik-at-kua.net