I have a motherboard that has three electrolytic caps that are bulging. I
have a 40watt iron with a chisel shaped bit that is just wide enough to
cover both wires of each capacitor at the same time. Would this rating be
enough to safely remove these by just heating and pulling them or am I
likely to cause damage by insufficient power. Each capacitor is 330uf/25v.
Hope that's enough info...

Thanks,
David

Subject: Removal of motherboard electrolytic caps
From: "David Sewell"
Date: 10/22/2004 1:59 PM Central Daylight Time
Message-id:

I have a motherboard that has three electrolytic caps that are bulging. I
have a 40watt iron with a chisel shaped bit that is just wide enough to
cover both wires of each capacitor at the same time. Would this rating be
enough to safely remove these by just heating and pulling them or am I
likely to cause damage by insufficient power. Each capacitor is 330uf/25v.
Hope that's enough info...

Thanks,
David

Hi, Dave. A heads-up here -- motherboards are multi-layer, and yanking the
leads out can result in tearing the connections between layers.

It's far better to cut off the top of the cap and gently heating each hole
individually. Very gentle here -- don't pull. It should practically come out
on its own.

Also, a 40 watt iron is a little heavy for PCB repair. Most people use around
a 25 watt iron for PCB repairs.

One other thing - don't just use any electrolytic cap here. You need an
aluminum electrolytic with low ESR, or it may be as bad or worse than nothing.

Good luck
Chris

"CFoley1064" wrote in message
...
Subject: Removal of motherboard electrolytic caps
From: "David Sewell"
Date: 10/22/2004 1:59 PM Central Daylight Time
Message-id:

I have a motherboard that has three electrolytic caps that are bulging.
I
have a 40watt iron with a chisel shaped bit that is just wide enough to
cover both wires of each capacitor at the same time. Would this rating
be
enough to safely remove these by just heating and pulling them or am I
likely to cause damage by insufficient power. Each capacitor is
330uf/25v.
Hope that's enough info...

Thanks,
David

Hi, Dave. A heads-up here -- motherboards are multi-layer, and yanking
the
leads out can result in tearing the connections between layers.

It's far better to cut off the top of the cap and gently heating each hole
individually. Very gentle here -- don't pull. It should practically come
out
on its own.

Also, a 40 watt iron is a little heavy for PCB repair. Most people use
around
a 25 watt iron for PCB repairs.

One other thing - don't just use any electrolytic cap here. You need an
aluminum electrolytic with low ESR, or it may be as bad or worse than
nothing.

Good luck
Chris

Thanks for that Chris,
I recall servicing GEC brand tv's many years ago, and they had double-sided
print, and they were a bit of a pain. That was a cinch compared to a
motherboard!! What made me think of a high power iron was because of
something I read in a forum about the solder on a motherboard being of a
higher melting point than normal. I had already tried an ordinary Antex
25watt iron and braid but it did not seem to be melting the solder - then
again the thing is so small my old eyes may have been deceiving me! Never
thought of cutting the cap itself. What sort of tool do you recommend and
do you mean the part of the cap as close as possible to the wire end?
Many thanks,
David

What made me think of a high power iron was because of
something I read in a forum about the solder on a motherboard being of a
higher melting point than normal.

The problem with using too hot of an iron is that the heat, if too high, can
cause damage to the pads.

Try a 30 watt iron. - Reinhart

To do it right, you really need a new tip and a good de-soldering
system.
I use a Pace, have years of experience, and still booger up a board
now and then. Multi layer boards are built real well, but you still
need
to do it correctly. See if one of your electronics pals has a
de-soldering
setup, and will do it for you.

"David Sewell" wrote in message
...
I have a motherboard that has three electrolytic caps that are
bulging. I
have a 40watt iron with a chisel shaped bit that is just wide enough
to
cover both wires of each capacitor at the same time. Would this
rating be
enough to safely remove these by just heating and pulling them or am
I
likely to cause damage by insufficient power. Each capacitor is
330uf/25v.
Hope that's enough info...

Thanks,
David

Thanks guys (or gals!) for your help. I will seek extra help from my local
spares supplier regarding desoldering. But not too optimistic as they are
geared towards the old traditional style tv spares and servicing.
Great help anyways,
There you go
Regardes,
David

Have a look here for DIY details
http://www.badcaps.net/tips/

Wayne

On Fri, 22 Oct 2004 19:59:12 +0100, "David Sewell"
wrote:

I have a motherboard that has three electrolytic caps that are bulging. I
have a 40watt iron with a chisel shaped bit that is just wide enough to
cover both wires of each capacitor at the same time. Would this rating be
enough to safely remove these by just heating and pulling them or am I
likely to cause damage by insufficient power. Each capacitor is 330uf/25v.
Hope that's enough info...

Thanks,
David

David Sewell wrote:
Thanks guys (or gals!) for your help. I will seek extra help from my local
spares supplier regarding desoldering. But not too optimistic as they are
geared towards the old traditional style tv spares and servicing.
Great help anyways,
There you go
Regardes,
David



FWIW, I recently did that job, and ended up drilling out the old leads.

BTW, use low ESR 105 degree C caps.

--
The e-mail address in our reply-to line is reversed in an attempt to
minimize spam. Our true address is of the form .

Kibo informs me that (CFoley1064) stated that:

Hi, Dave. A heads-up here -- motherboards are multi-layer, and yanking the
leads out can result in tearing the connections between layers.

It's far better to cut off the top of the cap and gently heating each hole
individually. Very gentle here -- don't pull. It should practically come out
on its own.

Good advice.

Also, a 40 watt iron is a little heavy for PCB repair. Most people use around
a 25 watt iron for PCB repairs.

Although I've found that 25W can be a little weak for working on
ground/power plane pads on multilayer boards, but as you said, 40W is a
little risky. Generally, it's best to use a good soldering station for
this sort of job, rather than a general-purpose iron.

One other thing - don't just use any electrolytic cap here. You need an
aluminum electrolytic with low ESR, or it may be as bad or worse than nothing.

A tantalum cap would be even better in this application. If you're
buying parts from a hobbyist shop, it can be quite difficult to find out
the the ESR rating of their electros, but standard tantalums are certain
to be correct.

--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------

Thanks, and the forum is great too.
http://www.badcaps.net/forum/

David

"Wayne" wrote in message news:4179b3d2.8344368@shawnews...
Have a look here for DIY details
http://www.badcaps.net/tips/

Wayne

On Fri, 22 Oct 2004 19:59:12 +0100, "David Sewell"
wrote:

I have a motherboard that has three electrolytic caps that are bulging.
I
have a 40watt iron with a chisel shaped bit that is just wide enough to
cover both wires of each capacitor at the same time. Would this rating
be
enough to safely remove these by just heating and pulling them or am I
likely to cause damage by insufficient power. Each capacitor is
330uf/25v.
Hope that's enough info...

Thanks,
David

Kibo informs me that "David Sewell"
stated that:

I recall servicing GEC brand tv's many years ago, and they had double-sided
print, and they were a bit of a pain. That was a cinch compared to a
motherboard!!

Yep.

What made me think of a high power iron was because of
something I read in a forum about the solder on a motherboard being of a
higher melting point than normal.

That's incorrect. The reason it seems that way is because motherboards
have huge ground & power planes on their own layers within the PCB,
which tend to act as heatsinks when you attempt to solder/desolder any
pins that connect to power or ground. Consequently, a light duty iron
will lose so much heat to the planes that the joint won't heat up enough
to melt the solder all the way through. Ideally, you need to use a
temperature-controlled iron with a heavy tip (I use a traditional,
ultra-reliable Weller TCP station myself, & strongly recommend them). If
you don't have access to a real iron like that, the next best thing is
to use a heavier standard iron - perhaps 30-40W or so - but you'll need
to be ultra careful not to damage the pads or cook the the surrounding
parts.

I had already tried an ordinary Antex
25watt iron and braid but it did not seem to be melting the solder - then
again the thing is so small my old eyes may have been deceiving me! Never
thought of cutting the cap itself. What sort of tool do you recommend and
do you mean the part of the cap as close as possible to the wire end?

The standard tool is a small pair of side-cutters, but I usually remove
electros by heating both pads with a blob of solder covering both, &
*gently* wiggling out the cap at the same time. (If a gentle touch
doesn't move the legs, the joints aren't yet hot enough - *do not* force
them, or you'll destroy the through-hole plating!)
Use whichever method you find easiest, with care, either will do the job
correctly.

--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------

I've alway done this by 1st heating the solder with a good temperature
controlled iron, and then sucking out the majority of the solder with a
plunger-type sucker. There are special static free solder suckers. The
iron tip should be clean with a nice thin, shinny coating of solder.
Sometimes to get the heat transferred fast, you much 1st add a bit of
fresh solder (with flux core) to help conduct the heat. This is
especially true on power or ground nets were there might be a lot of
copper on the board drawing away the heat. Once most of the solder is
gone, I touch the iron tip to the wire or pin (for a through-hole IC) on
the non-component side of the board, and try to push it away from the
hole walls. Many times, especially with a 2 terminal device, it will
fall out rather easily. Even through-hole IC will usually come out
without board damage.

Lionel wrote:

Kibo informs me that "David Sewell"
stated that:


I recall servicing GEC brand tv's many years ago, and they had double-sided
print, and they were a bit of a pain. That was a cinch compared to a
motherboard!!


Yep.


What made me think of a high power iron was because of
something I read in a forum about the solder on a motherboard being of a
higher melting point than normal.


That's incorrect. The reason it seems that way is because motherboards
have huge ground & power planes on their own layers within the PCB,
which tend to act as heatsinks when you attempt to solder/desolder any
pins that connect to power or ground. Consequently, a light duty iron
will lose so much heat to the planes that the joint won't heat up enough
to melt the solder all the way through. Ideally, you need to use a
temperature-controlled iron with a heavy tip (I use a traditional,
ultra-reliable Weller TCP station myself, & strongly recommend them). If
you don't have access to a real iron like that, the next best thing is
to use a heavier standard iron - perhaps 30-40W or so - but you'll need
to be ultra careful not to damage the pads or cook the the surrounding
parts.


I had already tried an ordinary Antex
25watt iron and braid but it did not seem to be melting the solder - then
again the thing is so small my old eyes may have been deceiving me! Never
thought of cutting the cap itself. What sort of tool do you recommend and
do you mean the part of the cap as close as possible to the wire end?


The standard tool is a small pair of side-cutters, but I usually remove
electros by heating both pads with a blob of solder covering both, &
*gently* wiggling out the cap at the same time. (If a gentle touch
doesn't move the legs, the joints aren't yet hot enough - *do not* force
them, or you'll destroy the through-hole plating!)
Use whichever method you find easiest, with care, either will do the job
correctly.

"Lionel" wrote in message
...
Kibo informs me that (CFoley1064) stated that:

Hi, Dave. A heads-up here -- motherboards are multi-layer, and yanking
the
leads out can result in tearing the connections between layers.

It's far better to cut off the top of the cap and gently heating each
hole
individually. Very gentle here -- don't pull. It should practically
come out
on its own.

Good advice.

Also, a 40 watt iron is a little heavy for PCB repair. Most people use
around
a 25 watt iron for PCB repairs.

Although I've found that 25W can be a little weak for working on
ground/power plane pads on multilayer boards, but as you said, 40W is a
little risky. Generally, it's best to use a good soldering station for
this sort of job, rather than a general-purpose iron.

If you try it with a 25W you'll never get them out, more likely you'll
overheat the board from having to keep the heat on it so long and the pads
will rip right off. I use a 140W Weller soldering gun for these, it's the
only way I've found to reliably heat the capacitor lead quickly enough to
remove it from the multilayer board without tearing things up. Conventional
rules do not apply here.