Re: 465B Attenuator servicing

Chuck Harris
 

Easy and cheap enough to get a pump sprayer bottle
from the store, and fill it with IPA. That is what
I do when I need to flood a circuit/switch/keyboard
with IPA.

-Chuck Harris

Colin Herbert via Groups.Io wrote:

OK, so the existence of spray-can IPA is new to me. Perhaps I should see if
I can get it in the UK, but it is cheap enough anyway and I apply it with
cotton-buds, tissues or slivers of paper, whichever is the best way for the
job. (It may be that the propellant is incompatible with the attenuator
substrate, of course).

Perhaps I can point out that the 465B Service Manual (mine covers B060000
and up) states that "carbon-based solvents will damage the boards used for
the attenuators. Apply the isopropyl alcohol with a camel hair brush. Do not
use cotton swabs.." This is at the bottom of page 6-3. I think that Tek
meant "carbon chloride-based solvents", as the isopropyl alcohol molecule
contains three carbon atoms. My 475A Service Manual further states that the
"attenuators use a plastic material (polyphenylene oxide) that is easily
damaged by the use of carbon-based solvents". It goes on to say that
"acetone, benzene, toluene, xylene, petroleum ether, white kerosene, carbon
tetrachloride, methylene chloride, trichloroethane, trichlorotrifluoroethane
(freon-113, -tf, -ta, -tmc) should not be used. As I said before, there are
a number of posts on the subject of cleaning these cam-actuated contacts on
this Forum. The gold-plated leaf contacts are delicate and easily damaged,
too. If you search, you should find the accepted technique - don't forget
that these cam-actuated contacts are common among most, if not all, of the
400-series portable scopes. I'm only trying to help to point you in the
right direction.

You could perhaps look at:

https://groups.io/g/TekScopes/message/144408?p=,,,20,0,0,0::Created,,cam+swi
tch+cleaning,20,2,0,11350196

(I hope the URL comes out ok).

Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of NigelP
Sent: 24 May 2019 10:02
To: TekScopes@groups.io
Subject: Re: [TekScopes] 465B Attenuator servicing

Thanks for your feedback.

Whilst I admit the specific tin I've just used does only have "Ambersil
Electronic Safety Solvent" written on it I have nevertheless used it
extensively for years. It has a long list of its suitability regarding
electronic circuits written on the can.

However to specifically answer your comment I can assure you that
pressurized cans of IPA DO exist and in fact I purchased one just this
weekend and it is sitting right in front of me as I write! It's called
Pro-Power PPC103 IPA Solvent.

Regards

Nigel










Join TekScopes@groups.io to automatically receive all group messages.