Good question, asked some of the folks I used to work with who were a part
of the engineering and manufacturing side around that time. It appears that
the 647A/11A2A and 11B2A was probably the last production instrument that
had volume use of the ceramic strip, but for practical purposes, yes, the
500 series as a line were the last. For a couple of scope generations
following, a ceramic strip or strips were used in a limited number of
products for special purposes, including one of the 7000 series plug-ins.
the 7A18.
Here is the original patent for the strips. And the internal spec for the
solder was 3% according to all the records I have or have seen. The iron was
typically a 50 W with a customized tip.
Now, anyone out there using a Rohn FK-25 foldover. If so, I've got a couple
of questions, have one setting all apart on sawhorses across my field.
Don W7WLL
-----Original Message-----
From: Al Kozakiewicz
Sent: Wednesday, November 04, 2015 6:23 AM
To: Don W7WLL ; Towertalk
Subject: Re: [TowerTalk] Solder For Connectors
Last generation of TUBE equipment. For oscilloscopes that would have been
the 500 series, no?
Al
AB2ZY
________________________________________
From: TowerTalk <towertalk-bounces@contesting.com> on behalf of Don W7WLL
<w7wll@arrl.net>
Sent: Tuesday, November 3, 2015 11:11 PM
To: Towertalk
Subject: Re: [TowerTalk] Solder For Connectors
Al, not sure why you say 'last generation'. Actually they went away many
generations ago.
For those interested in the history of Tek's ceramic strips (or need one)
see Stan, W7NI's web page -
http://www.reprise.com/ash/clients2/parts_shop/ceramic_strips.html. Stan was
a long time employee of Tek working both at the factory and as a Field
Engineer. I was with Tek from 1958 to 2001.
Here is another useful video on the correct way to solder Tek's ceramic
strips - http://www.vintagetek.org/ceramic-strip-soldering-techniques-1964/.
There is a lot of info on the internet about the original Tek ceramic strips
if you have the time to browse. I suspect a lot of we ex-Tek's have a hoard
of the old ceramic strips as well as some spools of the old 'silver solder',
many winding theirs on 120 or 620 film spools.
Don W7WLL
-----Original Message-----
From: Al Kozakiewicz
Sent: Tuesday, November 03, 2015 5:47 PM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] Solder For Connectors
By the way, the last generation of tube based Tektronix test equipment used
a point-to-point wiring system that consisted of leaded components soldered
to ceramic standoffs (think terminal strips with ceramic instead of bakelite
as the insulator) that had some kind of solderable metal terminals bonded to
the ceramic. These pieces of equipment had to use a silver based solder else
the metal would separate from the ceramic. The equipment had a small roll of
silver solder clipped on the chassis so that a repair technician had the
right stuff at hand.
Al
AB2ZY
-----Original Message-----
From: Al Kozakiewicz
Sent: Tuesday, November 03, 2015 8:27 PM
To: 'John Reilly'; towertalk@contesting.com
Subject: RE: [TowerTalk] Solder For Connectors
For the ham, virtually no advantages and one major disadvantage.
RoHS is a regulatory environment specific to the EU that regulates the
amount of lead that can be used in electronics that might end up in a
landfill. IMO, it has the same scientific basis as the anti-GMO movement
(also peculiar to the EU) in that it consists more of worry than facts.
The main disadvantage to a ham is the higher melting point of the Sn/Ag and
Sn/Ag/Cu solders, typically 40-80 degrees Fahrenheit higher than 63/37 or
60/40 Sn/Pb solder. An inconvenience when soldering something with a large
thermal mass (like the shell of a connector) or attempting a "toaster oven"
assembly of SMD parts on a circuit board as the melting point is right at
the temperature limit of your average Walmart toaster oven.
The big issue with RoHS when first introduced 12 years ago was the sudden
increase in tin whiskers causing the failure of highly miniaturized systems.
I, for one, would not want to have been one of the first patients to receive
a RoHS compliant pacemaker. Which, by the way, wasn't going to end up in a
landfill anyway unless you want to start calling cemeteries landfills! A lot
of high-tech work has been done to mitigate this risk, but then it is not a
problem that would affect anything a ham could solder without a microscope.
Al
AB2ZY
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of John
Reilly
Sent: Tuesday, November 03, 2015 7:53 PM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] Solder For Connectors
What are the advantages/disadvantages of using silver solder? I never have
gotten a clear understanding when silver solder is appropriate.
- 73, John, N0TA
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