Critical of Tektronix (was Tek 570 curve-tracer)


John Doran <johnd@...>
 

Howdy!



That German fellow's comments reminded me that, while I love

Tektronix and regard them highly, they have indeed done some seriously
bone-headed things over the years.



For example, in the 3A1 and 3A6 plug-in amplifiers for the 560 series
oscilloscopes, Tek had big, heavy rubber-covered resistors connected
directly to the fragile little terminals of plastic coil forms, with no
intermediate tie-points. I have one of each plug-in, and in each of
them the terminals have been snapped right off...



What was Tek thinking? ...Were they thinking?



I have not yet attempted to repair this damage; it looks tough.



-John


scoper796 <tekscopes@...>
 

Hi John,

Yes, I know whereof you speak. In fact, I stopped buying 3A6 plug-
ins, even thogh it is the best amp for the 560 series, because it is
impossible to find out if they are broken before purchase. And of
course I don't know of any source for replacements. I think they are
made of the same material as the disappearing crt clamps.

As far as repairing them go, I have the following to offer. The
little tiny wire is accessible, but I have had no luck getting the
varnish off it and soldering it. But that would work. I have bypassed
the peaking coils altogether, and that worked, but I didn't measure
the frequency response afterwards.

I would disagree that this is a mistake on Tektronics part. I know
they had no idea this equipment would still be in-use 40 years or so
after production. Even so, I have a 555 that is indestructible and I
am sure will work fine for another 40 years.

Good luck.

Larry Christopher



--- In TekScopes@yahoogroups.com, "John Doran" <johnd@e...> wrote:
Howdy!



That German fellow's comments reminded me that, while I love

Tektronix and regard them highly, they have indeed done some
seriously
bone-headed things over the years.



For example, in the 3A1 and 3A6 plug-in amplifiers for the 560
series


Dave Wise
 

From: scoper796 [mailto:tekscopes@telus.net]
[snip]
Yes, I know whereof you speak. In fact, I stopped buying 3A6 plug-
[snip]
little tiny wire is accessible, but I have had no luck getting the
varnish off it and soldering it. But that would work. I have bypassed
Sorry if it's been mentioned before, but aspirin is a pretty
good varnish remover. It's the acid. Lay the wire on an
aspirin tablet, hold your breath, and heat with a soldering iron.
The varnish should disappear quickly. Now wash off the acid
residue, and you're ready to tin the wire.

Dave Wise


regman10
 

Simply tinning the wire is usually a good varnish remover also. I use liquid
rosin flux as an enhancer.


Dave Wise
 

Yes, I save the aspirin trick for the tough ones.

Thanks,
Dave Wise

-----Original Message-----
From: Gary Allsebrook [mailto:regman10@comcast.net]
Sent: Thursday, December 02, 2004 10:55 AM
To: David Wise; scoper796; TekScopes@yahoogroups.com
Subject: RE: [TekScopes] Re: Critical of Tektronix (was Tek 570 curve-tracer)


Simply tinning the wire is usually a good varnish remover also. I use liquid rosin flux as an enhancer.


stefan_trethan
 

On Thu, 2 Dec 2004 10:26:57 -0800, David Wise <david_wise@phoenix.com> wrote:

Sorry if it's been mentioned before, but aspirin is a pretty
good varnish remover. It's the acid. Lay the wire on an
aspirin tablet, hold your breath, and heat with a soldering iron.
The varnish should disappear quickly. Now wash off the acid
residue, and you're ready to tin the wire.

Dave Wise

Do you know if that will eat away half my iron tip's plating?
I wonder about that a bit.. perhaps better use a old tip for the stunt..

ST


Dave Wise
 

Good point Stefan. I've only used it a couple of times,
with my Weller WTCP whose tips seem almost indestructible.

Dave Wise

-----Original Message-----
From: Stefan Trethan [mailto:stefan_trethan@gmx.at]
Sent: Thursday, December 02, 2004 12:06 PM
To: TekScopes@yahoogroups.com
Subject: Re: [TekScopes] Re: Critical of Tektronix (was Tek 570
curve-tracer)



On Thu, 2 Dec 2004 10:26:57 -0800, David Wise
<david_wise@phoenix.com>
wrote:

Sorry if it's been mentioned before, but aspirin is a pretty
good varnish remover. It's the acid. Lay the wire on an
aspirin tablet, hold your breath, and heat with a soldering iron.
The varnish should disappear quickly. Now wash off the acid
residue, and you're ready to tin the wire.

Dave Wise

Do you know if that will eat away half my iron tip's plating?
I wonder about that a bit.. perhaps better use a old tip for
the stunt..

ST


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scoper796 <tekscopes@...>
 

Jeez think what it must do to your stomach! Never mind 'lectricity!

Larry Christopher


--- In TekScopes@yahoogroups.com, "David Wise" <david_wise@p...>
wrote:
Good point Stefan. I've only used it a couple of times,
with my Weller WTCP whose tips seem almost indestructible.

Dave Wise

-----Original Message-----
From: Stefan Trethan [mailto:stefan_trethan@g...]
Sent: Thursday, December 02, 2004 12:06 PM
To: TekScopes@yahoogroups.com
Subject: Re: [TekScopes] Re: Critical of Tektronix (was Tek 570
curve-tracer)



On Thu, 2 Dec 2004 10:26:57 -0800, David Wise
<david_wise@p...>
wrote:

Sorry if it's been mentioned before, but aspirin is a pretty
good varnish remover. It's the acid. Lay the wire on an
aspirin tablet, hold your breath, and heat with a soldering
iron.
The varnish should disappear quickly. Now wash off the acid
residue, and you're ready to tin the wire.

Dave Wise

Do you know if that will eat away half my iron tip's plating?
I wonder about that a bit.. perhaps better use a old tip for
the stunt..

ST


------------------------ Yahoo! Groups Sponsor
--------------------~-->
$9.95 domain names from Yahoo!. Register anything.
http://us.click.yahoo.com/J8kdrA/y20IAA/yQLSAA/PMYolB/TM
--------------------------------------------------------------
------~->


Yahoo! Groups Links








Craig Sawyers <c.sawyers@...>
 

Simply tinning the wire is usually a good varnish remover also. I
use liquid
rosin flux as an enhancer.
It depends on the varnish used - some varnishes are designed to be soldered
through, so a hot iron and a good flux does the trick. There is a good
cross section of available wire coatings here

http://www.performance-coatings.org/en/industrial-coatings/ct-he-pi-electro-
wire-enamels.htm

Craig


matrafox2
 

--- In TekScopes@yahoogroups.com, "scoper796" <tekscopes@t...> wrote:
The
little tiny wire is accessible, but I have had no luck getting the
varnish off it and soldering it.

Hello,

If you have to solder a blank wire, you will apply the soldering iron
to its cylindrical surface, like the skilled in the art do.
If the wire is enamel coated, you have to forget routine because the
varnish has, opposite to copper a very low thermal conductance. All
the tiny amount of "heat" which can pass slowly through the insulator
will spread much more faster in the copper wire, cooling the inner
layer of the enamel and keeping it sticky.
The trick to avoid this is surprisingly simple. Cut the wire end to
have a plain clean surface and apply flux and solder to this blank
surface with the wire vertical to the soldering iron. Now there is a
better thermal contact through the immediately tinned copper wire
end. The varnish from the extremity will be eliminated faster because
its inner layer, which matters, is heated directly. The cylindrical
part simultaneously dived in the tin will soon get tinned. At this
point you may change the angle between the iron and wire and proceed
as usual.
So, the aspirin trick is not the only one to solder fragile coils.

Regards,
Hans


matrafox2
 

--- In TekScopes@yahoogroups.com, "matrafox2" <hans.wotsch@w...>
wrote:

--- In TekScopes@yahoogroups.com, "scoper796" <tekscopes@t...>
wrote:
The
little tiny wire is accessible, but I have had no luck getting
the
varnish off it and soldering it.

Hello,

If you have to solder a blank wire, you will apply the soldering
iron
to its cylindrical surface, like the skilled in the art do.
If the wire is enamel coated, you have to forget routine because
the
varnish has, opposite to copper a very low thermal conductance. All
the tiny amount of "heat" which can pass slowly through the
insulator
will spread much more faster in the copper wire, cooling the inner
layer of the enamel and keeping it sticky.
The trick to avoid this is surprisingly simple. Cut the wire end to
have a plain clean surface and apply flux and solder to this blank
surface with the wire vertical to the soldering iron. Now there is
a
better thermal contact through the immediately tinned copper wire
end. The varnish from the extremity will be eliminated faster
because
its inner layer, which matters, is heated directly. The cylindrical
part simultaneously dived in the tin will soon get tinned. At this
point you may change the angle between the iron and wire and
proceed
as usual.
So, the aspirin trick is not the only one to solder fragile coils.

Regards,
Hans
Sorry, I did't mention before that it is important to use more solder
as usual to have more of the wire end diving in the hot solder. And
enough flux, eg rosin too.

Regards,
Hans


Miroslav Pokorni
 

Tinning the magnet wire works only on wires insulated with 'lacquer'
formulated to decompose at higher temperature; one of such materials is
polyurethane and it takes 800 degree short tip of a Weller soldering iron.
If you try burning off insulation on old fashion lacquer, you got a job for
the whole day and probably would end up using a knife to scrape insulation
and gunk from burned up flux.

Regards

Miroslav Pokorni

----- Original Message -----
From: "Gary Allsebrook" <regman10@comcast.net>
To: "David Wise" <david_wise@phoenix.com>; "scoper796"
<tekscopes@telus.net>; <TekScopes@yahoogroups.com>
Sent: Thursday, December 02, 2004 10:54 AM
Subject: RE: [TekScopes] Re: Critical of Tektronix (was Tek 570
curve-tracer)


Simply tinning the wire is usually a good varnish remover also. I use
liquid
rosin flux as an enhancer.





Miroslav Pokorni
 

You are supposed to solder with it, not to eat it.

Regards

Miroslav Pokorni

----- Original Message -----
From: "scoper796" <tekscopes@telus.net>
To: <TekScopes@yahoogroups.com>
Sent: Thursday, December 02, 2004 12:57 PM
Subject: [TekScopes] Re: Critical of Tektronix (was Tek 570 curve-tracer)



Jeez think what it must do to your stomach! Never mind 'lectricity!

Larry Christopher


--- In TekScopes@yahoogroups.com, "David Wise" <david_wise@p...>
wrote:
Good point Stefan. I've only used it a couple of times,
with my Weller WTCP whose tips seem almost indestructible.

Dave Wise

-----Original Message-----
From: Stefan Trethan [mailto:stefan_trethan@g...]
Sent: Thursday, December 02, 2004 12:06 PM
To: TekScopes@yahoogroups.com
Subject: Re: [TekScopes] Re: Critical of Tektronix (was Tek 570
curve-tracer)



On Thu, 2 Dec 2004 10:26:57 -0800, David Wise
<david_wise@p...>
wrote:

Sorry if it's been mentioned before, but aspirin is a pretty
good varnish remover. It's the acid. Lay the wire on an
aspirin tablet, hold your breath, and heat with a soldering
iron.
The varnish should disappear quickly. Now wash off the acid
residue, and you're ready to tin the wire.

Dave Wise

Do you know if that will eat away half my iron tip's plating?
I wonder about that a bit.. perhaps better use a old tip for
the stunt..

ST


------------------------ Yahoo! Groups Sponsor
--------------------~-->
$9.95 domain names from Yahoo!. Register anything.
http://us.click.yahoo.com/J8kdrA/y20IAA/yQLSAA/PMYolB/TM
--------------------------------------------------------------
------~->


Yahoo! Groups Links










Miroslav Pokorni
 

How about a good, big blob of solder? That would transfer heat to insulator
in a hurry.

The Aspirin (a.k.a. Acidum Acetylsalicylicum) is more of an aggressive flux,
which eats up surface oxidation. It is great for difficult materials, like
stainless steel or corroded copper that you do not feel like cleaning. As
for after effects, once solidified, Aspirin does not seem to be nearly as
aggressive, but if you are concerned about residue, it can be burned off
quickly by heating the wire with soldering iron and not supplying any more
Aspirin.

Regards

Miroslav Pokorni

----- Original Message -----
From: "matrafox2" <hans.wotsch@web.de>
To: <TekScopes@yahoogroups.com>
Sent: Thursday, December 02, 2004 5:18 PM
Subject: [TekScopes] Re: Critical of Tektronix (was Tek 570 curve-tracer)



--- In TekScopes@yahoogroups.com, "scoper796" <tekscopes@t...> wrote:
The
little tiny wire is accessible, but I have had no luck getting the
varnish off it and soldering it.

Hello,

If you have to solder a blank wire, you will apply the soldering iron
to its cylindrical surface, like the skilled in the art do.
If the wire is enamel coated, you have to forget routine because the
varnish has, opposite to copper a very low thermal conductance. All
the tiny amount of "heat" which can pass slowly through the insulator
will spread much more faster in the copper wire, cooling the inner
layer of the enamel and keeping it sticky.
The trick to avoid this is surprisingly simple. Cut the wire end to
have a plain clean surface and apply flux and solder to this blank
surface with the wire vertical to the soldering iron. Now there is a
better thermal contact through the immediately tinned copper wire
end. The varnish from the extremity will be eliminated faster because
its inner layer, which matters, is heated directly. The cylindrical
part simultaneously dived in the tin will soon get tinned. At this
point you may change the angle between the iron and wire and proceed
as usual.
So, the aspirin trick is not the only one to solder fragile coils.

Regards,
Hans