[volt-nuts] 3458A - To Modify or Not To Modify?

[J. L. Trantham]

Well, the deed is done.  All chips removed without apparent problem.  All
chips archived although I am highly suspicious that the 'cal' chip died in
the process.  Very little data in the file.

I placed the 28 pin AMP closed frame gold plated IC sockets for the two
larger DALLAS chips.  The 40 pin and the 24 pin sockets are now 'on order'
along with replacement DALLAS chips.

These sockets are identical to the sockets for the Opt 001 sockets except
there is gold plating at the contacts.  The gold does not extend to the pins
that are soldered to the board.  The best I can do at keeping the board
'original'.

Very easy to remove the chips with my temp controlled Weller soldering iron
and 'de-solder braid'.

We'll see what I get when I place the sockets and return all chips to the
board.

Joe



-----Original Message-----
From: volt-nuts-bounces at febo.com [mailto:volt-nuts-bounces at febo.com] On
Behalf Of Chuck Harris
Sent: Sunday, November 06, 2011 10:21 PM
To: Discussion of precise voltage measurement
Subject: Re: [volt-nuts] 3458A - To Modify or Not To Modify?

Mark Sims wrote:
>
> Just because it's gold does not mean it's good.   You do not want to use
gold
> contacts with tin plated component pins...  nasty inter-metallic compounds
can
> form.  Also,  those lovely gold plated HP circuit boards are a no-no with
tin-lead
> solder joints.

Yes, it can be a bummer, the gold to solder joint sometimes only lasts
20 or 30 years before it fails.  When it does fail, touching it with
a hot soldering iron and adding a little more solder will do the trick.

-Chuck Harris

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