MessageView 421F schematic

[Jim Adney]

On Fri, 25 Feb 2005 22:57:54 GMT Sam Jacobson
<jacobson98@earthlink.net> wrote:

I am looking for a DM44 for my Tektronix 465B oscilloscope. If
anyone has one for sale, or know where I might get one, I would
appreciate you letting me know.

When I bought my 465B a number of years ago, I started thinking the
same thing. Fortunately, I had the complete service manual and I was
able to see how much work it would be to install, and I could also see
that it would make the scope much harder to get into if it ever needed
service.

Finally, I realized that most if its functions could be done better
with the newer instruments I already have. Do I gave up on this quest
and have never regretted it.

If you really want the DM44, you'd be much better off buying a
complete 465B/DM44 and selling your 465B.

BTW, the 465B is still a great scope. ;-)

-
-----------------------------------------------
Jim Adney jadney@vwtype3.org
Madison, WI 53711 USA
-----------------------------------------------

 

[John Woodgate]

I read in sci.electronics.design that Joerg <notthisjoergsch@removethisp
acbell.net> wrote (in <Kb6Ud.7462$OU1.5066@newssvr21.news.prodigy.com&gt
about 'Electrolytic caps?', on Sat, 26 Feb 2005:

Hello Watson,

Yes and yes, but it depends on how old those caps are. Over five years
old, and they're not 'fresh'; ten years and they're 'stale'.



Nah. I have some 40+ year old radios where the electrolytic caps are
just fine. A couple times I actually did a resistor charge and leakage
test just to see. They were nearly as good as new.

But sometimes when they had been in storage for decades they may have to
be "formatted" slowly to get them used to the job of "being a capacitor"
again.

It took a long time to discover that sodium chloride (common salt)
contamination was responsible for short life of aluminium electrolytic
capacitors, simply because traces of salt are almost everywhere. So if
your old caps have, by chance or design, a low salt content, they may
well still be good.
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

 

[Spehro Pefhany]

On Sat, 26 Feb 2005 15:04:30 -0700, the renowned Jim Thompson
<thegreatone@example.com> wrote:

On Sat, 26 Feb 2005 21:51:38 GMT, Joerg
notthisjoergsch@removethispacbell.net> wrote:

Hello Watson,

Yes and yes, but it depends on how old those caps are. Over five years
old, and they're not 'fresh'; ten years and they're 'stale'.



Nah. I have some 40+ year old radios where the electrolytic caps are
just fine. A couple times I actually did a resistor charge and leakage
test just to see. They were nearly as good as new.

But sometimes when they had been in storage for decades they may have to
be "formatted" slowly to get them used to the job of "being a capacitor"
again.

Regards, Joerg

http://www.analogconsultants.com

Hi, Joerg. I do, literally, have some 40 year-old aluminum
electrolytics in my part bins.

What's the best way to "format" them?

...Jim Thompson

It's actually "reform". Here's a web site that describes the process:

http://www.vcomp.co.uk/tech_tips/reform_caps/reform_caps.htm


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

 

[Melissa]

"Michael A. Terrell" <mike.terrell@earthlink.net> wrote :

Melissa wrote:

I used to work in electronics and have several large boxes of
electrolytic
caps in my lab. Does anyone still use them for anything? Is there even
any
electronics still being built in this country?

--
Yours In Liberty, Melissa - Colorado, U.S.A.
http://lakewoodcolorado.net/MailOrderPrototypes.htm

What type / voltage/ capacitance are they?

I don't recall, I'd have to go look. I have boxes of them all over the
place in my lab, which still hasn't been unpacked since we moved.

--
Yours In Liberty, Melissa - Colorado, U.S.A.
http://melissasliberty.blogspot.com/

The last best hope for liberty, to give the world its first Bill of
Rights: http://www.UPAlliance.org/billofrights.htm

 

[mc]

"Tim Wescott" <tim@wescottnospamdesign.com> wrote in message
news:1121vm3s9fi6a0b@corp.supernews.com...

Its "forming" (technically "reforming" since it was already done once at
the factory long long ago). You can do a web search on electrolytic
forming.

Basically you feed it rated voltage through a big current limiting
resistor -- what you're doing is restoring the aluminum oxide layer on the
foil. There are a number of techniques for verifying that the forming is
complete (vs. the cap being bad) -- basically when you think you're done
you test with more than the rated voltage to see if the thing leaks -- if
so, you scrap it.

I've never done it, but it's a common thing with tube-equipped boat
anchors.

The way I do it, which I thought was standard, was to gradually raise the
voltage from zero over a period of minutes, monitoring for leakage all the
time, and then leave it charged to the rated voltage for some time.

You can measure quite an increase in capacitance from doing this, even if
the capacitor didn't test out as defective to begin with.

 

[John Woodgate]

I read in sci.electronics.design that Michael A. Terrell
<mike.terrell@earthlink.net> wrote (in <42210247.53923FA3@earthlink.net>
) about 'Electrolytic caps?', on Sat, 26 Feb 2005:

Actually, after you re-form the oxide layer with a limited current
(<.1 ma) at the rated voltage you check the ESR to made sure the cap is
good. Any signs of leaked electrolyte automatically makes it a bad
part.

Both residual leakage current and ESR are important, but for ESR you
need some guidance on what is 'good' and 'bad'. It depends on a number
of factors.
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

 

[BFoelsch]

Personally, having played with electronics and salvaged parts since the
early 1950s, I think the whole "reforming" thing is pretty much baloney.

It's true, sometimes if you take an old electrolytic that tests poorly you
can get it to improve by using the "reforming" process. Often, however, the
resulting cap will have high ESR, and will want to leak for a while every
time you apply voltage to it.

I find that, in general, unless the leakage gets down to where it should be
in not more than maybe 15 seconds, the reformed cap is going to "deform"
spontaneously. There are some caps that will stop leaking over maybe 30
minutes, but if you test the rest of their properties you will often find
that you now have an electrolytic rectifier more than a capacitor.

That is not to say that all old electrolytic capacitors are bad. I recently
worked on an old Tek scope and the electrolytics with 1967 date codes were
perfectly good. However, electrolytics used in HP equipment of the same
vintage are almost always bad. I have some NOS capacitors that are fine, and
I just tossed a bunch that weren't.

I also worked on a 1992 fax machine recently. Every electrolytic cap was
leaking, both physically and electrically.

Test your old caps. Ramp them up to rated voltage while watching the
leakage. Don't overlook ESR. If they are good, keep them and use them. If
they are bad, toss them. I wouldn't put much faith in the reforming myth,
though.

"Tim Wescott" <tim@wescottnospamdesign.com> wrote in message
news:1121vm3s9fi6a0b@corp.supernews.com...

Jim Thompson wrote:

On Sat, 26 Feb 2005 21:51:38 GMT, Joerg
notthisjoergsch@removethispacbell.net> wrote:


Hello Watson,


Yes and yes, but it depends on how old those caps are. Over five years
old, and they're not 'fresh'; ten years and they're 'stale'.


Nah. I have some 40+ year old radios where the electrolytic caps are just
fine. A couple times I actually did a resistor charge and leakage test
just to see. They were nearly as good as new.

But sometimes when they had been in storage for decades they may have to
be "formatted" slowly to get them used to the job of "being a capacitor"
again.

Regards, Joerg

http://www.analogconsultants.com


Hi, Joerg. I do, literally, have some 40 year-old aluminum
electrolytics in my part bins.

What's the best way to "format" them?

...Jim Thompson

Its "forming" (technically "reforming" since it was already done once at
the factory long long ago). You can do a web search on electrolytic
forming.

Basically you feed it rated voltage through a big current limiting
resistor -- what you're doing is restoring the aluminum oxide layer on the
foil. There are a number of techniques for verifying that the forming is
complete (vs. the cap being bad) -- basically when you think you're done
you test with more than the rated voltage to see if the thing leaks -- if
so, you scrap it.

I've never done it, but it's a common thing with tube-equipped boat
anchors.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

 

[Watson A.Name - \"Watt Su]

"Jim Thompson" <thegreatone@example.com> wrote in message
news:sfs121h2dqjbg3aicp36p00ug9imp1sj2g@4ax.com...

On Sat, 26 Feb 2005 21:51:38 GMT, Joerg
notthisjoergsch@removethispacbell.net> wrote:

Hello Watson,

Yes and yes, but it depends on how old those caps are. Over five
years
old, and they're not 'fresh'; ten years and they're 'stale'.



Nah. I have some 40+ year old radios where the electrolytic caps are
just fine. A couple times I actually did a resistor charge and
leakage
test just to see. They were nearly as good as new.

But sometimes when they had been in storage for decades they may have
to
be "formatted" slowly to get them used to the job of "being a
capacitor"
again.

Regards, Joerg

http://www.analogconsultants.com

Hi, Joerg. I do, literally, have some 40 year-old aluminum
electrolytics in my part bins.

What's the best way to "format" them?

www.vcomp.co.uk/tech_tips/reform_caps/reform_caps.htm

...Jim Thompson
--

 

[Watson A.Name - \"Watt Su]

"Grass roots" <Grass-roots@no-email.net> wrote in message
news:Xns9609BC310E38CTOKEN@216.196.97.142...

"Watson A.Name - \"Watt Sun, the Dark Remover\""
NOSPAM@dslextreme.com
wrote :


"Melissa" <melissa@colorado.xxx> wrote in message
news:QYedncdMwIethb3fRVn-3A@forethought.net...
I used to work in electronics and have several large boxes of
electrolytic
caps in my lab. Does anyone still use them for anything? Is there
even
any
electronics still being built in this country?

Yes and yes, but it depends on how old those caps are. Over five
years
old, and they're not 'fresh'; ten years and they're 'stale'.

And that means what?

It means that if the cap you are going to use is that old, you had
better not assume that it has the rated capacitance at the rated
voltage. So measure it and find out for certain.

--
Grassroots
( no email - spoofed )

 

[Melissa]

Melissa <melissa@colorado.xxx> wrote :

"Michael A. Terrell" <mike.terrell@earthlink.net> wrote :

Melissa wrote:


I don't recall, I'd have to go look. I have boxes of them all over the
place in my lab, which still hasn't been unpacked since we moved.

Here, I have a huge case of these, for starters:
http://dimensional.com/~melissa/photos/Cap1500uf100v.JPG


--
Yours In Liberty, Melissa - Colorado, U.S.A.
http://melissasliberty.blogspot.com/

The last best hope for liberty, to give the world its first Bill of
Rights: http://www.UPAlliance.org/billofrights.htm

 

[Pooh Bear]

Melissa wrote:

Melissa <melissa@colorado.xxx> wrote :

"Michael A. Terrell" <mike.terrell@earthlink.net> wrote :

Melissa wrote:


I don't recall, I'd have to go look. I have boxes of them all over the
place in my lab, which still hasn't been unpacked since we moved.


Here, I have a huge case of these, for starters:
http://dimensional.com/~melissa/photos/Cap1500uf100v.JPG

As they're designed for hand wiring as opposed to pcb mount, I doubt many
ppl would be interested in them these days.

You could always try shifting them on ebay though.


Graham

 

[Pooh Bear]

mc wrote:

"Tim Wescott" <tim@wescottnospamdesign.com> wrote in message
news:1121vm3s9fi6a0b@corp.supernews.com...

Its "forming" (technically "reforming" since it was already done once at
the factory long long ago). You can do a web search on electrolytic
forming.

Basically you feed it rated voltage through a big current limiting
resistor -- what you're doing is restoring the aluminum oxide layer on the
foil. There are a number of techniques for verifying that the forming is
complete (vs. the cap being bad) -- basically when you think you're done
you test with more than the rated voltage to see if the thing leaks -- if
so, you scrap it.

I've never done it, but it's a common thing with tube-equipped boat
anchors.

The way I do it, which I thought was standard, was to gradually raise the
voltage from zero over a period of minutes, monitoring for leakage all the
time, and then leave it charged to the rated voltage for some time.

I wouldn't call that the standard method but ramping the voltage sounds like a
nice idea. You still want to use a current limiting resistor though.

You also need to apply the rated voltage for some time IIRC to ensure that the
oxide film is fully reformed.

You can measure quite an increase in capacitance from doing this, even if
the capacitor didn't test out as defective to begin with.

As compared to the rated capacitance ?


Graham

 

[Pooh Bear]

John Woodgate wrote:

I read in sci.electronics.design that Joerg <notthisjoergsch@removethisp
acbell.net> wrote (in <Kb6Ud.7462$OU1.5066@newssvr21.news.prodigy.com&gt
about 'Electrolytic caps?', on Sat, 26 Feb 2005:
Hello Watson,

Yes and yes, but it depends on how old those caps are. Over five years
old, and they're not 'fresh'; ten years and they're 'stale'.



Nah. I have some 40+ year old radios where the electrolytic caps are
just fine. A couple times I actually did a resistor charge and leakage
test just to see. They were nearly as good as new.

But sometimes when they had been in storage for decades they may have to
be "formatted" slowly to get them used to the job of "being a capacitor"
again.

It took a long time to discover that sodium chloride (common salt)
contamination was responsible for short life of aluminium electrolytic
capacitors, simply because traces of salt are almost everywhere. So if
your old caps have, by chance or design, a low salt content, they may
well still be good.

Talking of salt messing things up....

Do you recall that GEC did a deal with Nat Semi IIRC to make a UK cmos fab
back in the 70s ?

One of the lecturers at UCL had been there and taught us semiconductor
physics. They could never get the process fixed. The chips would work - but
'go bad' after some months.

It was finally found that the the nichrome wire that they were using in the
ovens was quenched in a salt solution during the manufacturing process.
Sodium ions were 'boiling out' of the wire and entering the chips. Initially
this caused no problem until the sodium ions migrated into the active region
and threw the threshold voltages of the fets all over the place.

Sadly the problem was diagnosed too late and the project was dropped.


Graham

 

[Barry & Nikki]

PLEASE PLEASE PLEASE let me know when you are going target practicing. My
wife OKed my purchase of the AR-10 I had been looking at and I got it as my
Valentines present. Always looking for anything to "plink" with it. Can you
hook power up to the boards and get them to run away; nothing better than
honing skills on a moving target.


"Melissa" <melissa@colorado.xxx> wrote in message
news:R8GdncLahapJor_fRVn-tw@forethought.net...

Does anyone know what this is and if it might be worth anything? I have a
whole big box of them, packed in anti-static bags.

http://dimensional.com/~melissa/photos/Optotech%201178%20boards.JPG

I suppose if no one wants them, I could always use 'em for shooting
targets.

 

[Melissa]

Pooh Bear <rabbitsfriendsandrelations@hotmail.com> wrote :

Melissa wrote:

Does anyone know what this is and if it might be worth anything? I have
a whole big box of them, packed in anti-static bags.

http://dimensional.com/~melissa/photos/Optotech%201178%20boards.JPG

I suppose if no one wants them, I could always use 'em for shooting
targets.

Conceivably an interface board from some piece of kit presumably made by
Optotech Inc.

Nothing of any real value there, although those optocouplers look of
intruiging construction.

Several things intrigue me. Here's a bigger better photo:
http://dimensional.com/~melissa/photos/Optotech%201178%20boards2.JPG
look at that optical device in the lower right. One red and one green? What
is that?

What's a VQ1006J by the way? I've been out of the field for awhile but
don't recall those.


--
Yours In Liberty, Melissa - Colorado, U.S.A.
http://melissasliberty.blogspot.com/

The last best hope for liberty, to give the world its first Bill of
Rights: http://www.UPAlliance.org/billofrights.htm

 

[Melissa]

nospam <nospam@nospam.invalid> wrote :

Melissa <melissa@colorado.xxx> wrote:

Does anyone know what this is and if it might be worth anything? I have a
whole big box of them, packed in anti-static bags.

http://dimensional.com/~melissa/photos/Optotech%201178%20boards.JPG

It is a control PCB from some ancient optical disk drive (from around
1987). If the drives were ever in production they must have been
obsolete
years ago so it will be worth nothing as a spare part and slightly more
than nothing for the parts which could be salvaged from it.

Optotech don't seem to be around anymore but were in Colorado Springs.

http://www.optotech.com/


--
Yours In Liberty, Melissa - Colorado, U.S.A.
http://melissasliberty.blogspot.com/

The last best hope for liberty, to give the world its first Bill of
Rights: http://www.UPAlliance.org/billofrights.htm

 

[Watson A.Name - \"Watt Su]

"Pooh Bear" <rabbitsfriendsandrelations@hotmail.com> wrote in message
news:4222608A.D8502E31@hotmail.com...

Melissa wrote:

Melissa <melissa@colorado.xxx> wrote :

"Michael A. Terrell" <mike.terrell@earthlink.net> wrote :

Melissa wrote:


I don't recall, I'd have to go look. I have boxes of them all over
the
place in my lab, which still hasn't been unpacked since we moved.


Here, I have a huge case of these, for starters:
http://dimensional.com/~melissa/photos/Cap1500uf100v.JPG

As they're designed for hand wiring as opposed to pcb mount, I doubt
many
ppl would be interested in them these days.

You could always try shifting them on ebay though.

Audio repair guys can use those for the DC blocking cap on the output
stage of power amps.

Graham

 

[Robert Baer]

Melissa wrote:

Pooh Bear <rabbitsfriendsandrelations@hotmail.com> wrote :


Melissa wrote:


Does anyone know what this is and if it might be worth anything? I have
a whole big box of them, packed in anti-static bags.

http://dimensional.com/~melissa/photos/Optotech%201178%20boards.JPG

I suppose if no one wants them, I could always use 'em for shooting
targets.

Conceivably an interface board from some piece of kit presumably made by
Optotech Inc.

Nothing of any real value there, although those optocouplers look of
intruiging construction.



Several things intrigue me. Here's a bigger better photo:
http://dimensional.com/~melissa/photos/Optotech%201178%20boards2.JPG
look at that optical device in the lower right. One red and one green? What
is that?

What's a VQ1006J by the way? I've been out of the field for awhile but
don't recall those.


Sorry about my previous response; the reference was not available.

I see no gold, and unless you needed some electrolytics, etc - the
best bet is try some local electronic surplus dealers.

 

[Rich Grise]

On Sun, 27 Feb 2005 22:30:48 -0600, Melissa wrote:

Several things intrigue me. Here's a bigger better photo:
http://dimensional.com/~melissa/photos/Optotech%201178%20boards2.JPG
look at that optical device in the lower right. One red and one green? What
is that?

I don't see anything in that photo that matches this description. What are
you talking about? I see a couple of diode symbols with red background
near the upper-middle center; a couple of electrolytics in the upper
left; a header connector bottom left; and in the lower right corner, if
you're talking about the PCB, rather than the keyboard it's sitting on, I
see a C-shaped blue-grey shape like a wood-worker's clamp. I even see the
VQ1006J, below the 74HC86, and above the clamp-looking thing.

But nothing matching the description, "one red and one green".

What am I missing?

Thanks,
Rich

 

[Rich Grise]

On Mon, 28 Feb 2005 07:24:20 +0000, Robert Baer wrote:

Melissa wrote:

Does anyone know what this is and if it might be worth anything? I have a
whole big box of them, packed in anti-static bags.

http://dimensional.com/~melissa/photos/Optotech%201178%20boards.JPG

I suppose if no one wants them, I could always use 'em for shooting targets.

If you have a really large quantity of PC boards, some of the parts
are worthwhile (batteries, socketed ICs like the CPU and BIOS), and the
*GOLD* on them is well worth finding a recycler that handles such items.
Find at least three, know how many pounds (maybe better yet board
area) and get quotes.
They will deduct costs of reclaimation but usually pay spot value
(use Kitco for reference).

The landlord at the building where I sit does gold.

I could check if they're interested in that sort of thing, if you light
a fire under my ass. ;-)

Cheers!
Rich