A number of the switches on the 465 use PC board pads as contacts. They
have heavy gold plating, but eventually the gold wears off. When that
happens, the switch is dead and as far as I know can't be repaired. You
might be able to squeeze a little more life out of it by cleaning, but
in any case I'd be very careful not to use a cleaner with any abrasive
qualities. If cleaning doesn't cure the problem, worn pads might be the
cause.

But by all means check with the 'scope newsgroup. I'm sure you'll find
folks who have had a lot of experience with the 465, and some might even
know of some kind of fix or replacement for worn switch contact pads.

Roy Lewallen, W7EL

"Highland Ham" wrote in
:


If it were mine, I would first try a spritz of contact cleaner into
the switch via the front panel slot (IIR465C). All contact
cleaners are the same - mineral oil and alcohol - so the cheapest
Radio Shack stuff works as well as anything. WD40 also works well.
==============================
On various occsasions I have been told that WD40 is NOT the right
cleaning agent for electrical systems involving plastic insulation re
wiring, etc. I always use (non chlorinated) contact cleaner as
available from Rat Shack and similar stores.
Here in the UK I use contact cleaner supplied by Maplin.

Frank GM0CSZ / KN6WH




On TEK LF or HF cam style contact switches,do NOT use mineral oil-based
cleaner/lubes.Take some 99% isopropyl alco,wet a narrow paper strip,and
slide under the closed contact,and move back and forth.These cam-style
switches have VERY low wiping force,and any oil,grease,or film will cause
intermittents or opens.

I suspect a calibration may improve his triggering,too.

--
Jim Yanik
jyanik-at-kua.net

Don Lancaster wrote in :




Clean the switches with Radio Shack tuner cleaner.


No.Use 99% isopropyl alcohol.

--
Jim Yanik
jyanik-at-kua.net

In article ,
. says...
Don Lancaster wrote in :




Clean the switches with Radio Shack tuner cleaner.


No.Use 99% isopropyl alcohol.


You know, it's funny how often these debates flare up over a subject as
mundane as contact cleaner. "My tuner cleaner is better than your tuner
cleaner. Your tuner cleaner should be used only in Ukrainian opposition
candidates' minestrone. My tuner cleaner costs more than HP printer
ink. If you spray your tuner cleaner on a Tektronix 465, it will
trigger a resonance cascade and gate in alien overlords from the planet
Xen." Yadda, yadda, yadda.

Despite all the gurus out there forking the evil eye at WD-40, I sure
seem to own a lot of stuff that still works fine after being sprayed
with WD-40 over the years (decades, in some cases). Yeah, I know.
"Data: n, plural of 'anecdote'."

Some of these gurus are admittedly respected veterans of companies such
as Tektronix, with whom mere mortals are loath to argue. All I can say
is, those switches must not have been of the greatest quality in the
first place, or the gurus wouldn't have to spend so much of their time
on Usenet warning people against hosing them down with WD-40.

Just sayin', is all. No disrespect intended.

-- jm

------------------------------------------------------
http://www.qsl.net/ke5fx
Note: My E-mail address has been altered to avoid spam
------------------------------------------------------

"John Miles" schreef in bericht
...

[snip]

Some of these gurus are admittedly respected veterans of companies such
as Tektronix, with whom mere mortals are loath to argue. All I can say
is, those switches must not have been of the greatest quality in the
first place, or the gurus wouldn't have to spend so much of their time
on Usenet warning people against hosing them down with WD-40.

LOL. Well, some switches on oscilloscopes are very fragile with many,
many contacts, and rather low contact pressure. Sometimes hermetically
sealed too, so you can even use a spray can of Spam or shaving foam and
it won't hurt a bit

--
Thanks, Frank.
(remove 'q' and 'invalid' when replying by email)

The discussion about contact cleaner isn't altogether mundane.

I worked at Tek for many years, although I'm certainly not a guru when
it comes to oscilloscope maintenance. But I do recall one experience
with cleaning solvents and board-mounted switches.

Before introducing a new instrument, we went through a lengthy process
of building and testing prototypes, which I described some time ago in
this newsgroup. In one group, it was our practice to borrow some
assemblers from production to build the prototypes. One afternoon I was
looking at some units they had built, after they had left for the day,
and saw that the plastic of some switch bodies was very badly crazed --
they were covered with tiny cracks. Some experiments with bottles of
solvent we found in some of the assemblers' work areas pinned it down to
one particular liquid. The problem was one of the ingredients, which was
a relatively common solvent of the time. Unfortunately, I don't recall
which one -- it was something pretty mild as solvents go, like toluene
or Freon, not a relatively strong solvent like acetone, which we all
knew better than to use. We found out that the solvent had been banned
from production, but the assemblers kept a supply out of sight because
it was really good at removing flux.

The lesson is that even some normally pretty innocent solvents can
destroy some plastics. Other components can also be ruined by various
solvents, so that's another reason to use some caution. As just one
example, it was found that Freon and its relatives would migrate up the
leads and into even pretty well sealed radial leaded aluminum
electrolytic capacitors, corroding the insides and causing premature
failure. This was solved by improving the end seals, but only after a
lot of the older type reached the field, some on boards having been
washed with Freon. Of course, Freon is no longer used, but there are a
host of other potential problems. It's ultimately up to you to decide
whether you want to experiment with your scope.

As for WD-40, I love the stuff and use it on all kinds of switches and
electrical components. But I mentioned a short while ago that the cam
switches in the 465 and some other scopes use PC board pads for
contacts, and when the pad's gold plating is gone, the switch -- and the
scope -- is dead. So it doesn't seem like a good thing to me to use a
cleaner on those that'll leave a film which can collect dust or anything
abrasive.

I don't agree that a switch's ability to withstand WD-40 or any other
particular chemical is an indicator of its quality. But we all have our
own criteria we use to judge.

Roy Lewallen, W7EL

John Miles wrote:

You know, it's funny how often these debates flare up over a subject as
mundane as contact cleaner. "My tuner cleaner is better than your tuner
cleaner. Your tuner cleaner should be used only in Ukrainian opposition
candidates' minestrone. My tuner cleaner costs more than HP printer
ink. If you spray your tuner cleaner on a Tektronix 465, it will
trigger a resonance cascade and gate in alien overlords from the planet
Xen." Yadda, yadda, yadda.

Despite all the gurus out there forking the evil eye at WD-40, I sure
seem to own a lot of stuff that still works fine after being sprayed
with WD-40 over the years (decades, in some cases). Yeah, I know.
"Data: n, plural of 'anecdote'."

Some of these gurus are admittedly respected veterans of companies such
as Tektronix, with whom mere mortals are loath to argue. All I can say
is, those switches must not have been of the greatest quality in the
first place, or the gurus wouldn't have to spend so much of their time
on Usenet warning people against hosing them down with WD-40.

Just sayin', is all. No disrespect intended.

-- jm

------------------------------------------------------
http://www.qsl.net/ke5fx
Note: My E-mail address has been altered to avoid spam
------------------------------------------------------

"Highland Ham" wrote

WD40 is NOT the right cleaning agent for electrical systems
involving plastic insulation re wiring, etc.

That was also my impression. But I have used it on plastics and
have not found any problems after 20 years. Famous last words,
I know. I have used it as a contact cleaner with great success.

--
Nicholas O. Lindan, Cleveland, Ohio
Consulting Engineer: Electronics; Informatics; Photonics.
Remove spaces etc. to reply: n o lindan at net com dot com
psst.. want to buy an f-stop timer? nolindan.com/da/fstop/

"Roy Lewallen" wrote

cam switches in the 465 and some other scopes use PC board pads for
contacts, and when the pad's gold plating is gone, the switch -- and the
scope -- is dead.

It is possible to re-plate the gold. But imagining the circuit board
it may be impossible to mask the components. Aw, what the heck - gold
plate the whole thing and screw it to your Hinkley yacht.

--
Nicholas O. Lindan, Cleveland, Ohio
Consulting Engineer: Electronics; Informatics; Photonics.
Remove spaces etc. to reply: n o lindan at net com dot com
psst.. want to buy an f-stop timer? nolindan.com/da/fstop/

John Miles wrote in
:

Some of these gurus are admittedly respected veterans of companies
such as Tektronix, with whom mere mortals are loath to argue.

I worked for TEK for 21.5 years as a service tech in 2 of their field
offices;repaired and cal'd a lot of scopes and other TEK products.

All I
can say is, those switches must not have been of the greatest quality
in the first place, or the gurus wouldn't have to spend so much of
their time on Usenet warning people against hosing them down with
WD-40.

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.


Just sayin', is all. No disrespect intended.

-- jm

Same here.

--
Jim Yanik
jyanik-at-kua.net

If there's any disagreement between what I say and what Jim says about
maintaining Tek scopes, listen to Jim and not me. He was there in the
trenches; I wasn't.

Roy Lewallen, W7EL

Jim Yanik wrote:

I worked for TEK for 21.5 years as a service tech in 2 of their field
offices;repaired and cal'd a lot of scopes and other TEK products.
. . .