general question: mainboard caps

[Meat Plow]

On Wed, 22 Sep 2010 09:23:21 -0700, Jeff Liebermann wrote:

<snip>

I've been soldering for about 50 years, so I suspect I'm sufficiently
experienced to have made all the usual mistakes (several times). It's
not the lack of skill.

<snip>

My first "job" in electronics was in the back room of my barber's shop
who had a little hobby business repairing electronics odds and ends. It
was where I learned how to solder. Especially after being told by one of
the barber's friends that I soldered like his grandmother That was in
1971. I was 16.



--
Live Fast, Die Young and Leave a Pretty Corpse

 

[Daniel Mandic]

Michael wrote:

Ok, thanks to everyone who replied. Seems doable... looks like I'm
going shopping for a vacuum desolderer.

Hi Michael!


Makes repair surely easier . It's always my advice, but I don't have
an desoldering-iron (vacuum) since then ;-). The 'right' stuff is
expensive....

I have done some boards, desoldering the failing condensators by
changing the soldering-iron from one pin to the other, pulling the
capacitor side (pin) by side (pin), out of its placement.
The new caps I pull into the same way....
Tin-solder I take only a tip..., just to have a better contact to the
origin tin-solder of the mainboard, which can be tricky and sticky :-(.

Some boards are easier, and you can desolder it with desoldering-lace
(flex, cord). Plus, that the standard (yours) tin-solder will be
adopted, too.


--
Daniel Mandic

 

[Michael]

On Sep 22, 9:23 am, Jeff Liebermann <je...@cruzio.com> wrote:

On Wed, 22 Sep 2010 05:05:19 +0000 (UTC), Sergey Kubushyn

k...@koi8.net> wrote:
Jeffrey Angus <jan...@suddenlink.net> wrote:
On 9/21/2010 11:29 PM, Sergey Kubushyn wrote:
I recently restored and fully recapped two Kenwood KA-9100 amps. All the
boards are phenolic and I used solder braid on them.

And they are not multi layer boards with 0.010" traces.

They are not. There is no such thing as _phenolic_ multi layer boards with
0.010" traces.

Not yet.  Some experiments in printed semiconductors and 3D circuits
use multilayer boards.  However they don't use solder.  They're
stapled together.  They're also intended to be throw away assemblies,
so I wouldn't worry about repair.

BTW, solder braid is very useful on _ANY_ board, including multilayer ones
with 0.010" traces. It requires some skills of course but everything does. I
do use it all the time.

I've been soldering for about 50 years, so I suspect I'm sufficiently
experienced to have made all the usual mistakes (several times).  It's
not the lack of skill.  I have no problem using braid on large objects
with small heat sinks.  I have nothing but problems using braid on
small objects attached to large heat sinks.  I this case, there's a
small leaded capacitor, connected to a rather large copper heat sink
of the power bus inside the PCB.  You can see the effect when
unsoldering the capacitor leads.  The ungrounded hot lead comes out
easily.  The grounded lead is far more difficult.  If the capacitors
are near the CPU and on a power bus, then both leads are difficult.
Braid is also quite suitable for unsolder connections where the solder
is easily accessible and exposed to the braid, such as large xformer
pins, terminal strips, wire terminals, some IC sockets, tube sockets,
etc.  

I noticed that one of the capacitor leads is connected to what looks
like a fat copper trace (ground?) The other lead seems soldered to
just a tiny little circle... if I hadn't looked closely, I might have
soldered it to ground by mistake too...

Also remember that this is for what appears to be a beginner at
repair.  It's easier to explain how to operate a solder sucker than
braid.

Yes I'm a beginner at this, and thanks!

I forgot to mention the desoldering bulb, another device that barely
works:
http://www.amazon.com/Weller-Desoldering-Bulb-Solder-Off/dp/B00011TUZY
The only good part is that it's great finger exercise (I play piano).

I heard that the bulb doesn't work very well. My dad has one. And
hey, I play the piano too! Trying to learn how to play George
Winston's piano solos... The Cradle is pretty straightforward, but, oh
man, his variations on the Carol of the Bells is extremely tough!

Michael

 

[Jeff Liebermann]

On Wed, 22 Sep 2010 18:55:13 +0000 (UTC), Meat Plow
<mhywatt@yahoo.com> wrote:

On Wed, 22 Sep 2010 11:11:56 -0700, Jeff Liebermann wrote:

On Wed, 22 Sep 2010 16:31:39 +0000 (UTC), Meat Plow <mhywatt@yahoo.com
wrote:

On Wed, 22 Sep 2010 09:23:21 -0700, Jeff Liebermann wrote:

snip

I've been soldering for about 50 years, so I suspect I'm sufficiently
experienced to have made all the usual mistakes (several times). It's
not the lack of skill.

snip

My first "job" in electronics was in the back room of my barber's shop
who had a little hobby business repairing electronics odds and ends. It
was where I learned how to solder. Especially after being told by one of
the barber's friends that I soldered like his grandmother That was in
1971. I was 16.

That was a compliment.

I started with an Ungar wood burner at about 14 years old. The first
lesson I learned is that the power cord of the iron will melt and short
when I place the iron on it. It was downhill from there as my father
taught me to use a large copper gas fired furnace soldering thing used
to make industrial sewing machine attachments. By comparison, the Ungar
seemed easy. After several years of doing everything wrong, the high
skool electric shop teacher introduced me to flux. Over the years, I
learned the basics, like you can hold solder in your mouth, but don't
try it with copper wire. Far too many Eico, Heathkit, and Knightkit
constructions were great practice.

I recently tried to teach a friends 14 year old brat how to solder. He's
hopeless, but dedicated, and will eventually learn.

LOL! We had wood burners but I think I was only 10. I can't imagine the
politics of selling those thing to children of that age as a child's toy
these days.

I can't recall how old I was when I got the wood burner, so I guessed
on the age. I may have been younger. Mine hand a huge ceramic
heating element, with a diameter about the same as the handle. There
was no way to put it down anywhere without seriously burning what it
touched. The unplated tiny copper screw-in tip was a bad joke that
pitted badly after a few hours of use. The handle got really hot. I
had it for maybe 30 years and used it for cutting and welding plastic.
By todays standards, the old woodburners are dangerous even for an
adult.


--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Jeff Liebermann]

On Wed, 22 Sep 2010 11:42:53 -0700 (PDT), Michael
<mrdarrett@gmail.com> wrote:

I noticed that one of the capacitor leads is connected to what looks
like a fat copper trace (ground?) The other lead seems soldered to
just a tiny little circle... if I hadn't looked closely, I might have
soldered it to ground by mistake too...

Some of the traces and pads are VERY close to nearby grounds and other
traces. Be careful and don't slop too much solder around when you
install the replacement cap.

I heard that the bulb doesn't work very well. My dad has one.

Steal the bulb, throw it away, and get him a solder sucker. Better
yet, steal just the teflon tip. It fits some solder suckers.

hey, I play the piano too! Trying to learn how to play George
Winston's piano solos... The Cradle is pretty straightforward, but, oh
man, his variations on the Carol of the Bells is extremely tough!

I can't read a note of music and scribble my own. My playing is awful
but given a few centuries practice, it might improve:
<http://802.11junk.com/jeffl/music/>
My Korg DDS-1 synthesizer slowly died over the last month and is
scattered in pieces all over the living room. I can't tell what
failed, but it's making strange noises and the LCD backlighting has
quit. Yet another project. Playing music is the only thing that
keeps me sane, which may explain this months rants on usenet.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Meat Plow]

On Wed, 22 Sep 2010 11:11:56 -0700, Jeff Liebermann wrote:

On Wed, 22 Sep 2010 16:31:39 +0000 (UTC), Meat Plow <mhywatt@yahoo.com
wrote:

On Wed, 22 Sep 2010 09:23:21 -0700, Jeff Liebermann wrote:

snip

I've been soldering for about 50 years, so I suspect I'm sufficiently
experienced to have made all the usual mistakes (several times). It's
not the lack of skill.

snip

My first "job" in electronics was in the back room of my barber's shop
who had a little hobby business repairing electronics odds and ends. It
was where I learned how to solder. Especially after being told by one of
the barber's friends that I soldered like his grandmother That was in
1971. I was 16.

That was a compliment.

I started with an Ungar wood burner at about 14 years old. The first
lesson I learned is that the power cord of the iron will melt and short
when I place the iron on it. It was downhill from there as my father
taught me to use a large copper gas fired furnace soldering thing used
to make industrial sewing machine attachments. By comparison, the Ungar
seemed easy. After several years of doing everything wrong, the high
skool electric shop teacher introduced me to flux. Over the years, I
learned the basics, like you can hold solder in your mouth, but don't
try it with copper wire. Far too many Eico, Heathkit, and Knightkit
constructions were great practice.

I recently tried to teach a friends 14 year old brat how to solder. He's
hopeless, but dedicated, and will eventually learn.

LOL! We had wood burners but I think I was only 10. I can't imagine the
politics of selling those thing to children of that age as a child's toy
these days.



--
Live Fast, Die Young and Leave a Pretty Corpse

 

[Daniel Mandic]

larry moe 'n curly wrote:

With any iron, a chisel tip, about
2mm - 2.5mm wide, works better than a conical tip, and tips are best
cleaned with curly brass hair or a damp paper towel, not a sponge.

A good watered sponge does work. Good condition solder-tip expected...


So many Tips and Tricks you gave, I don't think Michael will understand
the halve of it ;-)


--
Daniel Mandic

 

[Daniel Mandic]

Jeff Liebermann wrote:

I can't read a note of music and scribble my own. My playing is awful
but given a few centuries practice, it might improve:
http://802.11junk.com/jeffl/music/
My Korg DDS-1 synthesizer slowly died over the last month and is
scattered in pieces all over the living room. I can't tell what
failed, but it's making strange noises and the LCD backlighting has
quit. Yet another project. Playing music is the only thing that
keeps me sane, which may explain this months rants on usenet.

Some people do have only one hit in their life, but.
E.g. 'Scatman'. Or...!... 'Born to be Alive'!

With this in mind, play your melodies and enjoy the time. I do so...


[Yamaha AN1-X, KORG DSS-1, Wavestation, .....and some DiY, preferably
analogue, in my mind! ;-) e.g. MiniMOOG, TR-909, Formant Synthesizer,
etc., much work AND high costs....]


--
Daniel Mandic

 

[Daniel Mandic]

Michael wrote:

That reminds me... is it a good idea or a bad idea to solder the new
cap with normal (leaded) solder?

Mainboards, AFAIK, are soldered in an solder bath. I don't know the
temperature nor the solder-tin they use. Even that, I would have no
idea what to do with the data ;-)

I do by trying. Believing my skills (can excel to rubbish quality, if I
don't keep the pace regarding IT motherboards) might help.

But you can make some repairs if you dare, and save some money here and
there. (I am starting to rhyme in english... )

Keep an eye, as other posters said (take a lens for example!), for
solder- spots/patches/splotches, where they shouldn't be.


By the way. Power capacitors are, I would say, arranged to the bottom
side of the mainboard. The pins of the cap goes through the board.
I have had similar thoughts as you... 8layer, 4layer special
electronic, but, so long as I have had bringing back PC's, I am pretty
sure power caps are to be found on the bottom side (physically on the
top side, off course).


--
Daniel Mandic

 

[Michael]

On Sep 22, 1:09 pm, "Daniel Mandic" <daniel_man...@hotmail.com> wrote:

Michael wrote:
Ok, thanks to everyone who replied.  Seems doable... looks like I'm
going shopping for a vacuum desolderer.

Hi Michael!

Makes repair surely easier . It's always my advice, but I don't have
an desoldering-iron (vacuum) since then ;-). The 'right' stuff is
expensive....

I have done some boards, desoldering the failing condensators by
changing the soldering-iron from one pin to the other, pulling the
capacitor side (pin) by side (pin), out of its placement.
The new caps I pull into the same way....
Tin-solder I take only a tip..., just to have a better contact to the
origin tin-solder of the mainboard, which can be tricky and sticky :-(.

Some boards are easier, and you can desolder it with desoldering-lace
(flex, cord). Plus, that the standard (yours) tin-solder will be
adopted, too.

--
Daniel Mandic

That reminds me... is it a good idea or a bad idea to solder the new
cap with normal (leaded) solder?

Thanks,

Michael

 

[Michael]

On Sep 22, 2:00 pm, "Daniel Mandic" <daniel_man...@hotmail.com> wrote:

larry moe 'n curly wrote:

With any iron, a chisel tip, about
2mm - 2.5mm wide, works better than a conical tip, and tips are best
cleaned with curly brass hair or a damp paper towel, not a sponge.

A good watered sponge does work. Good condition solder-tip expected...

So many Tips and Tricks you gave, I don't think Michael will understand
the halve of it ;-)

--
Daniel Mandic

Dad always used a sponge (repaired TVs and radios decades ago) for
solder work. I prefer a used tissue personally. (A sponge is such a
waste.)

Michael

 

[Michael A. Terrell]

Michael wrote:

On Sep 22, 2:00 pm, "Daniel Mandic" <daniel_man...@hotmail.com> wrote:
larry moe 'n curly wrote:

With any iron, a chisel tip, about
2mm - 2.5mm wide, works better than a conical tip, and tips are best
cleaned with curly brass hair or a damp paper towel, not a sponge.

A good watered sponge does work. Good condition solder-tip expected...

So many Tips and Tricks you gave, I don't think Michael will understand
the halve of it ;-)

--
Daniel Mandic

Dad always used a sponge (repaired TVs and radios decades ago) for
solder work. I prefer a used tissue personally. (A sponge is such a
waste.)

Then why is the industry standard for manufacturing? They can be
rinsed out and turned over. Even with heavy use, they have a long
life. Also, it is much easier to keep them damp that a dirty kleenex.
You do not want the sponge to be sopping wet, just damp enough to keep
it from burning. If it is too wet it can cause the iron plating to
crack, and cause the tip to have a very short life.


--
Politicians should only get paid if the budget is balanced, and there is
enough left over to pay them.

 

[Michael A. Terrell]

Michael wrote:

What? There is still electronics manufacturing in the United States?

Yes, just not $10 radios or $20 TVs.


--
Politicians should only get paid if the budget is balanced, and there is
enough left over to pay them.

 

[Jeff Liebermann]

On Wed, 22 Sep 2010 13:57:28 -0700 (PDT), Michael
<mrdarrett@gmail.com> wrote:

That reminds me... is it a good idea or a bad idea to solder the new
cap with normal (leaded) solder?

No. It's highly likely that the motherboard uses RoHS blessed
unleaded solder. Mixing solder types results in a rather dull looking
cold solder joint. However, if you suck away all of the solder on the
pad, you can probably get away with switching solder types, but I
wouldn't bother. Just get the right solder.

Incidentally, I have two soldering irons on my bench... one for each
type of solder.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Michael]

On Sep 22, 8:52 pm, "Michael A. Terrell" <mike.terr...@earthlink.net>
wrote:

Michael wrote:

On Sep 22, 2:00 pm, "Daniel Mandic" <daniel_man...@hotmail.com> wrote:
larry moe 'n curly wrote:

With any iron, a chisel tip, about
2mm - 2.5mm wide, works better than a conical tip, and tips are best
cleaned with curly brass hair or a damp paper towel, not a sponge.

A good watered sponge does work. Good condition solder-tip expected....

So many Tips and Tricks you gave, I don't think Michael will understand
the halve of it ;-)

--
Daniel Mandic

Dad always used a sponge (repaired TVs and radios decades ago) for
solder work.  I prefer a used tissue personally.  (A sponge is such a
waste.)

   Then why is the industry standard for manufacturing?  They can be

What? There is still electronics manufacturing in the United States?
8-D

 

[Michael]

On Sep 22, 9:40 pm, "Michael A. Terrell" <mike.terr...@earthlink.net>
wrote:

Michael wrote:

What?  There is still electronics manufacturing in the United States?

   Yes, just not $10 radios or $20 TVs.

Will wonders never cease... ok, I'm taking half of my wife's
dishwashing sponge then...

Michael

 

[Michael A. Terrell]

Michael wrote:

On Sep 22, 9:40 pm, "Michael A. Terrell" <mike.terr...@earthlink.net
wrote:
Michael wrote:

What? There is still electronics manufacturing in the United States?

Yes, just not $10 radios or $20 TVs.


Will wonders never cease... ok, I'm taking half of my wife's
dishwashing sponge then...

Is it a real sponge, or just a fake plastic version? Spend the
couple bucks and by one treated for cleaning soldering iron tips.


--
Politicians should only get paid if the budget is balanced, and there is
enough left over to pay them.

 

On Sep 21, 6:51 pm, Jeff Liebermann <je...@cruzio.com> wrote:

On Tue, 21 Sep 2010 11:28:35 -0700 (PDT), Michael

mrdarr...@gmail.com> wrote:
Ok, thanks to everyone who replied.  Seems doable... looks like I'm
going shopping for a vacuum desolderer.

While a proper vacuum desoldering station is nice, you can get away
with using a solder sucker.
http://www.amazon.com/SOLDER-SUCKER-DESOLDERING-DESOLDER-REMOVAL/dp/B...
It requires some practice at both using and cleaning.  I use one when
I'm too lazy to fire up the desoldering station.

Someone suggested using solder braid.  I disagree.  I've lifted so
many traces and pads from the board with solder braid, that I won't
use it unless I'm depserate.

Don't forget the stainless steel needle or pin for cleaning the hole.
--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558
#http://802.11junk.com              je...@cruzio.com
#http://www.LearnByDestroying.com              AE6KS

I'm with you on the braid but it _is_ good for cleaning surface mount
pads before installing the new component. A Metcal with an STTC-126
tip is about the best if you _don't_ have a vacuum desoldering
station. The small tip can fit partway into the hole after the
component is out and then you can use an old fashioned solder sucker
with excellent results.

G˛

 

[Jeff Liebermann]

On Wed, 22 Sep 2010 23:15:47 -0700 (PDT), Michael
<mrdarrett@gmail.com> wrote:

Will wonders never cease... ok, I'm taking half of my wife's
dishwashing sponge then...

Don't do that. It's probably a plastic immitation sponge. It will
melt or burn nicely, even with sufficient water. The real soldering
iron sponges are cellulose and cost about $1 online. You can find
cellulose sponges at the market if you read the label carefully.

The other problem is that the household sponges are too thick. After
a few minutes, the water will dribble back into the base of the
sponge, leaving the top of the sponge quite dry and easy to burn. Too
thin is also a problem as you don't want to submerge the soldering
iron tip into a puddle of water. I'm too lazy to walk downstairs and
measure the official Weller sponge thickness, but try to get it close.
For a holder, I find glass ashtrays to be perfect.


--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Bob Villa]

On Sep 21, 9:44 am, Jeff Liebermann <je...@cruzio.com> wrote:

On Mon, 20 Sep 2010 12:52:38 -0700 (PDT), Michael

mrdarr...@gmail.com> wrote:
I've got a couple of Intel boards (D865PERL) that have one bad
electrolytic capacitor each.  One board stopped working; the other
still works, but has a bulging cap close to the CPU area.  (Pics not
yet available.)

My experience is that if you have the usual 8-10 identical capacitors
on the motherboard, and one is visibly defective, then the others are
highly likely to fail very soon.  I replace *ALL* the caps of a
specific type.  In particular, the caps around the CPU tend to die,
because of the heat and the high ripple current.  Typically, I'll
replace 10 to 15 caps.

Is desoldering these caps straightforward?

It varies.  Some boards are very easy to unsolder.  Others have
smaller holes for the leaded parts and are more difficult.  A vacuum
desoldering station is best.  Use plenty of heat and some liquid flux
so that you don't pull the plated thru hole out with the capacitor. If
you see a copper colored ring around a capacitor lead, you've probably
killed the board.

Any special precautions
re: multi-layered PCB traces?

If you don't have a tip that will heat both leads at the same time, or
don't have 3 arms so that you can use two soldering irons, all is not
lost.  I heat up one lead, and rock the capacitor in the opposite
direction.  After it moves a little, I heat the other lead, and rock
it in the opposite direction.  Don't use brute force or you'll rip out
the plated through holes.  Eventually, it comes out.  

One lead is usually grounded where the large copper area acts as an
effective heat sink.  This lead will be more difficult to unsolder
than the hot lead (usually +).  I use a big, wide (1/4"), hot (850C),
chisel tip.  Plenty of heat, and work fast.  This will take some
practice.  Find an old PCB and practice a little before attacking the
Intel motherboard.

Any special gotchas to keep in mind
when ordering replacement caps from say Mouser?

105C Low-ESR.  Watch the case dimensions and lead spacing.  If it will
fit, try to buy the next higher voltage rating.  I'm partial to
Panasonic but will use Rubycon.  Digikey, Mouser, and eBay (in that
order).  I sometimes use polymer caps as replacements, when the
motherboard is worth fixing and the customer doesn't care about the
cost.  Also, think about buying an ESR tester if you're going to make
a habit of this.

http://www.badcaps.net
http://www.afrotechmods.com/groovy/capacitor_replacement/capacitor_re...
http://en.wikipedia.org/wiki/Capacitor_plague
http://www.capacitorlab.com

--
Jeff Liebermann     je...@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

Thanks to all for your expertise in de-soldering...there is a world of
experience here, and worth much.
I have never had luck with braided wire...but evidently is works for
some. (I never have any luck with super-glue either!)