Hello,

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.)

Is desoldering these caps straightforward? Any special precautions
multi-layered PCB traces? Any special gotchas to keep in mind
when ordering replacement caps from say Mouser?

Thanks,

Michael

On 9/20/2010 2:52 PM, Michael wrote:
Hello,

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.)

Is desoldering these caps straightforward? Any special precautions
multi-layered PCB traces? Any special gotchas to keep in mind
when ordering replacement caps from say Mouser?

I fully recapped a pair of Dell Optoplex GX-280 mother boards.
About 15 or so caps per board.

Using a vacuum desoldering tool is the best method, but you can
remove the caps but using a wide enough tip to hit both leads
at the same time, then go back and clean the solder out of the holes
with a piece of stainless steel like a dental pick. Melt, stuff,
let cool and remove.

On the caps look for "low esr" and 105C temperature range. I try to
buy Nichicon caps by default. At $1 or so apiece, it's not worth saving
a few cents to get a crap cap that won't last.

Jeff

Jeffrey Angus wrote in message
...
On 9/20/2010 2:52 PM, Michael wrote:
Hello,

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.)

Is desoldering these caps straightforward? Any special precautions
multi-layered PCB traces? Any special gotchas to keep in mind
when ordering replacement caps from say Mouser?

I fully recapped a pair of Dell Optoplex GX-280 mother boards.
About 15 or so caps per board.

Using a vacuum desoldering tool is the best method, but you can
remove the caps but using a wide enough tip to hit both leads
at the same time, then go back and clean the solder out of the holes
with a piece of stainless steel like a dental pick. Melt, stuff,
let cool and remove.

On the caps look for "low esr" and 105C temperature range. I try to
buy Nichicon caps by default. At $1 or so apiece, it's not worth saving
a few cents to get a crap cap that won't last.

Jeff


If you can clamp to the cap and pull at the same time it helps, I use a
surgical instrument like arterial forceps but longer opening arms and full
gripping teeth (retraction clamp?).
For the cleaning out of holes I made up a set of needle probes from
different sized st/st sewing needles glued into ballpoint pen barrels or
into drilled dowel

No 16 of part of my tool kit is the specific clamp
http://www.diversed.fsnet.co.uk/tools_s.jpg
if anyone should happen to know the medical name for.
Number 17 are surgical terminology "Spencer Wells" , good for heatsinking
etc

goggling , probably Baby-Allis forceps

On Mon, 20 Sep 2010 12:52:38 -0700 (PDT), Michael
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
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_replacement.htm
http://en.wikipedia.org/wiki/Capacitor_plague
http://www.capacitorlab.com


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

On Sep 21, 9:44*am, Jeff Liebermann wrote:
On Mon, 20 Sep 2010 12:52:38 -0700 (PDT), Michael

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



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

Michael

On Sep 21, 11:28*am, Michael wrote:

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

For a one-off project, desoldering braid (it sucks up solder like a
sponge)
is almost as good, and doesn't have the sticker-shock effect.

Practice on a scrap board or two FIRST. It's easy to damage
things while the iron is hot and the polymers are soft.

On Tue, 21 Sep 2010 11:28:35 -0700 (PDT), Michael
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/B0002Y8OPM
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
# http://www.LearnByDestroying.com AE6KS

On 9/21/2010 8:51 PM, Jeff Liebermann wrote:
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 desperate.

About the only thing solder braid is good for is phenolic PC boards
with brass rivets for the through holes.

That and lifting traces.

Jeff (the other other one)

Jeffrey Angus wrote:

On 9/21/2010 8:51 PM, Jeff Liebermann wrote:
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 desperate.

About the only thing solder braid is good for is phenolic PC boards
with brass rivets for the through holes.

That and lifting traces.


And cleaning the solder off the pins of Octal tubes.


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

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* * * * * * *
#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.

G²

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

On Sep 22, 1:09*pm, "Daniel Mandic" 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 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

On Wed, 22 Sep 2010 13:57:28 -0700 (PDT), Michael
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
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On Sep 21, 9:44*am, Jeff Liebermann wrote:
On Mon, 20 Sep 2010 12:52:38 -0700 (PDT), Michael

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
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 * *
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!)

On Thu, 23 Sep 2010 10:40:39 -0700 (PDT), Bob Villa
wrote:

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!)

Super-glue doesn't do very well for desoldering (or soldering) a
printed circuit boards.

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

On Sep 24, 6:00*am, Jeff Liebermann wrote:
On Thu, 23 Sep 2010 10:40:39 -0700 (PDT), Bob Villa

wrote:
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!)

Super-glue doesn't do very well for desoldering (or soldering) a
printed circuit boards. *

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

This was unrelated and anecdotal. But, thanks again.

On Sep 24, 12:45*pm, Bob Villa wrote:
On Sep 24, 6:00*am, Jeff Liebermann wrote:



On Thu, 23 Sep 2010 10:40:39 -0700 (PDT), Bob Villa

wrote:
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!)

Super-glue doesn't do very well for desoldering (or soldering) a
printed circuit boards. *

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

This was unrelated and anecdotal. But, thanks again.



On that note, I have had better luck with a pick axe than a
shovel... :-D (when cutting into the side of the backyard slope, not
on circuit boards)

On Sep 24, 2:45*pm, Bob Villa wrote:
On Sep 24, 6:00*am, Jeff Liebermann wrote:



On Thu, 23 Sep 2010 10:40:39 -0700 (PDT), Bob Villa

wrote:
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!)

Super-glue doesn't do very well for desoldering (or soldering) a
printed circuit boards. *

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

This was unrelated and anecdotal. But, thanks again.

Well, actually, it is related...many ppl seem to be able to get
satisfactory results using braid to de-solder and getting super glue
to stick to the proper thing. (note: not necessarily the same ppl or
at the same time) I do not.
HTMS

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

Hello,

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.)

Is desoldering these caps straightforward? Any special precautions
multi-layered PCB traces? Any special gotchas to keep in mind
when ordering replacement caps from say Mouser?

Thanks,

Michael

I've done this on motherboards; it's tedious, but practical. The
suggestions from others are good. Here's a few things I discovered.

While vacuum desoldering tools work well, you have to heat the board
to the point where the solder on the ground lead melts all the way
through the board. The vacuum desoldering tools aren't real efficient
at transfereing heat unless you add a little solder or flux to each
lead you are going to unsolder.

The technique I settled on was to use a 40 watt soldering iron with a
chisel tip. Heat up one leg, add a dab of Chip-Quik, rock the cap
toward the opposite side. Heat up the other leg, add Chip-Quik, rock
cap to other side. Repeat with the heating and rocking until the cap
drops out. While it's still hot, push an iron or stanless steel
needle through the hole (I use a dissecting pick I got in the '60's).
Remove the pick when the solder has cooled; reheat the other hole and
use the needle.

Make sure you keep a chart identifying which cap goes where. Patience
is necessary. Make sure you clean up all stray solder.

PlainBill

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

Hello,

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.)

Is desoldering these caps straightforward? Any special precautions
multi-layered PCB traces? Any special gotchas to keep in mind
when ordering replacement caps from say Mouser?

Thanks,

Michael

I've done this on motherboards; it's tedious, but practical. The
suggestions from others are good. Here's a few things I discovered.

While vacuum desoldering tools work well, you have to heat the board
to the point where the solder on the ground lead melts all the way
through the board. The vacuum desoldering tools aren't real efficient
at transfereing heat unless you add a little solder or flux to each
lead you are going to unsolder.

The technique I settled on was to use a 40 watt soldering iron with a
chisel tip. Heat up one leg, add a dab of Chip-Quik, rock the cap
toward the opposite side. Heat up the other leg, add Chip-Quik, rock
cap to other side. Repeat with the heating and rocking until the cap
drops out. While it's still hot, push an iron or stanless steel
needle through the hole (I use a dissecting pick I got in the '60's).
Remove the pick when the solder has cooled; reheat the other hole and
use the needle.

Make sure you keep a chart identifying which cap goes where. Patience
is necessary. Make sure you clean up all stray solder.

PlainBill

Good advise and also make sure you take note of the polarity.

On Sep 21, 4:59*pm, "tm" wrote:
wrote in message

...



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

Hello,

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.)

Is desoldering these caps straightforward? *Any special precautions
multi-layered PCB traces? *Any special gotchas to keep in mind
when ordering replacement caps from say Mouser?

Thanks,

Michael

I've done this on motherboards; it's tedious, but practical. *The
suggestions from others are good. *Here's a few things I discovered.

While vacuum desoldering tools work well, you have to heat the board
to the point where the solder on the ground lead melts all the way
through the board. *The vacuum desoldering tools aren't real efficient
at transfereing heat unless you add a little solder or flux to each
lead you are going to unsolder.

The technique I settled on was to use a 40 watt soldering iron with a
chisel tip. *Heat up one leg, add a dab of Chip-Quik, rock the cap
toward the opposite side. *Heat up the other leg, add Chip-Quik, rock
cap to other side. *Repeat with the heating and rocking until the cap
drops out. *While it's still hot, push an iron or stanless steel
needle through the hole (I use a dissecting pick I got in the '60's).
Remove the pick when the solder has cooled; reheat the other hole and
use the needle.

Make sure you keep a chart identifying which cap goes where. *Patience
is necessary. *Make sure you clean up all stray solder.

PlainBill

Good advise and also make sure you take note of the polarity.


Yes... I was having visions of getting the cap out then wondering,
which way is negative... :-D

Thanks y'all

Michael

Michael wrote:

Yes... I was having visions of getting the cap out then wondering,
which way is negative... :-D

Usually there's a circle printed on the board under each electrolytic
capacitor, and the negative side is filled in, but Asus and Asrock
boards are marked the opposite way, so the filled area indicates the
positive lead instead.

There are YouTube videos about soldering and desoldering, and
BadCaps.net has a lot of information and also sells high-quality
caps. I think they also have a YouTube video.

In my novice opinion, a mainboard made with leaded solder needs a 40W
iron to solder it, a 50W iron to desolder it, and lead-free boards
need even more power. But a regular 50W iron can overheat its tip and
turn it blue or oxidize it, which really hurts heat conduction. There
are adjustable power irons for as little as $10, but I've found that
cheap irons don't last long or don't deliver as much heat to the tip
as good irons of the same power rating. BTW if you buy one off Ebay,
check the voltage because many are made only for 220VAC. If you're
going to spend much at all on an iron, consider getting a temperature-
controlled, 70W Goot PX-201, about $50, which should be able to handle
about anything, and Goot is a quality brand. Temperature-controlled
is better than adjustable power. 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.

Manual desoldering vacuums work best if you can hold them on one side
of the board and the iron on the other side and see both sides at
once. Vacuum bulbs don't suck nearly as well as spring plungers do,
but the latter can strike and damage board at the moment the spring is
released. Addng a short length of rubber tubing can prevent the
damage.

Copper desoldering braid works if it's the right width (enough to soak
up all the solder from the hole in one try but not more, generally
2-3mm and the iron puts out plenty of heat. Cut off the used portion
immediately after use so it won't absorb heat from the next joint.
Don't pull out a lead unless all of the solder from the hole has been
removed, and test by wiggling the lead side to side. Generally if all
the solder doesn't come out in one try, it's best to fill the hole
with 60/40 or 63/37 solder and start all over.

Chip Quik may be the easiest and safest way to desolder because it
melts at under 150F, but it costs about $1 per inch.

Radio Shack sells an $11 desoldering iron with a vacuum bulb, and
other sources have a similar tool that has a spring-loaded plunger
vacuum instead. The Radio Shack iron doesn't seem to deliver quite
enough heat to the tip for multilayer boards, but people have modified
it with a better vacuum pump or by wrapping heat insulation above the
tip.

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

On Sep 22, 2:12*am, "larry moe 'n curly"
wrote:
Michael wrote:
Yes... I was having visions of getting the cap out then wondering,
which way is negative... :-D

Usually there's a circle printed on the board under each electrolytic
capacitor, and the negative side is filled in, but Asus and Asrock
boards are marked the opposite way, so the filled area indicates the
positive lead instead.

There are YouTube videos about soldering and desoldering, and
BadCaps.net has a lot of information and also sells high-quality
caps. *I think they also have a YouTube video.

In my novice opinion, a mainboard made with leaded solder needs a 40W
iron to solder it, a 50W iron to desolder it, and lead-free boards
need even more power. *But a regular 50W iron can overheat its tip and
turn it blue or oxidize it, which really hurts heat conduction. *There
are adjustable power irons for as little as $10, but I've found that
cheap irons don't last long or don't deliver as much heat to the tip
as good irons of the same power rating. *BTW if you buy one off Ebay,
check the voltage because many are made only for 220VAC. * If you're
going to spend much at all on an iron, consider getting a temperature-
controlled, 70W Goot PX-201, about $50, which should be able to handle
about anything, and Goot is a quality brand. * Temperature-controlled
is better than adjustable power. *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.

Manual desoldering vacuums work best if you can hold them on one side
of the board and the iron on the other side and see both sides at
once. *Vacuum bulbs don't suck nearly as well as spring plungers do,
but the latter can strike and damage board at the moment the spring is
released. *Addng a short length of rubber tubing can prevent the
damage.

Copper desoldering braid works if it's the right width (enough to soak
up all the solder from the hole in one try but not more, generally
2-3mm and the iron puts out plenty of heat. *Cut off the used portion
immediately after use so it won't absorb heat from the next joint.
Don't pull out a lead unless all of the solder from the hole has been
removed, and test by wiggling the lead side to side. *Generally if all
the solder doesn't come out in one try, it's best to fill the hole
with 60/40 or *63/37 solder and start all over.

Chip Quik may be the easiest and safest way to desolder because it
melts at under 150F, but it costs about $1 per inch.

Radio Shack sells an $11 desoldering iron with a vacuum bulb, and
other sources have a similar tool that has a spring-loaded plunger
vacuum instead. *The Radio Shack iron doesn't seem to deliver quite
enough heat to the tip for multilayer boards, but people have modified
it with a better vacuum pump or by wrapping heat insulation above the
tip.


Went shopping... got a plunger for $11 at Fry's. Harbor Freight has a
180W solder gun for $10... remembered pointers here on high power for
Pb-free solder... is the gun a good idea, or too hot?