Motherboard repair question.

[Richard Brooks]

Out of interest, has anyone here done simple repairs such as
electrolytic capacitor replacement on a motherboard ?

Although not a motherboard, I'd successfully done this by replacing a
single capacitor (and replaced a link) on an audio line on an old
Hauppauge WinTV card that was inside a muddy computer that had literally
been thrown out but I was wondering if anyone has done this with a
larger piece of kit ?

Richard.

 

[meow2222]

Out of interest, has anyone here done simple repairs such as
electrolytic capacitor replacement on a motherboard ?

Although not a motherboard, I'd successfully done this by replacing a
single capacitor (and replaced a link) on an audio line on an old
Hauppauge WinTV card that was inside a muddy computer that had literally
been thrown out but I was wondering if anyone has done this with a
larger piece of kit ?

Richard.

I've not found it worth doing on pc mobos yet, as I mainly work with
older kit atm, but its a fairly straightforward job. The one issue is
if you go the unsoldering route its easy to break a thin trace pulling
an old cap out. Safer to piggyback than pull them out, and usually
works fine.


NT

 

[Rod Speed]

Out of interest, has anyone here done simple repairs such as electrolytic capacitor
replacement on a motherboard ?

Yep, plenty have.

Although not a motherboard, I'd successfully done this by replacing a single capacitor
(and replaced a link) on an audio line on an old
Hauppauge WinTV card that was inside a muddy computer that had
literally been thrown out but I was wondering if anyone has done this
with a larger piece of kit ?

Yep, plenty have.

Even easier in power supplys.

 

[paulmd]

Out of interest, has anyone here done simple repairs such as
electrolytic capacitor replacement on a motherboard ?

Although not a motherboard, I'd successfully done this by replacing a
single capacitor (and replaced a link) on an audio line on an old
Hauppauge WinTV card that was inside a muddy computer that had literally
been thrown out but I was wondering if anyone has done this with a
larger piece of kit ?

Richard.

The motherbard has to be pretty expensive to justify recapping. And,
well the ones that need recapping just aren't....... But if the
motherboard is a freebie, and you can do the work yourself, and have
the parts already, there's no reason you shouldn't do it.

 

[kony]

Out of interest, has anyone here done simple repairs such as
electrolytic capacitor replacement on a motherboard ?

Yes I do it quite often.

Although not a motherboard, I'd successfully done this by replacing a
single capacitor (and replaced a link) on an audio line on an old
Hauppauge WinTV card that was inside a muddy computer that had literally
been thrown out but I was wondering if anyone has done this with a
larger piece of kit ?

.... and there must be some followup information here? I'll
throw out a few random comments.

It's no big deal really, not as hard as some would suggest.
I've never pulled up a trace with the cap and the random
idea some have about multi-layer boards being an issue is
nonsense, any through-board caps have plated through-board
holes that desolder same as if it wasn't a multi-layer board
(meaning only two layers, top and bottom). Surface mount
caps can be more difficult especially if positioned very
near other parts, so in that case you may need a very high
heat iron and very long tip, probably small chisel tips work
best here. As on other work, having the right sized tip
that is in good condition (clean, tinned well, and not
eroded away) can be important (or at least a lot easier).
You can make do with a sub-optimal shaped tip often but it
just depends on the exact scenario.

On some of them you'll have small signal traces very near
the cap leads so you need a steady hand and a higher heat
fine-tipped iron... also presuming some general soldering
experience and a way you're proficient at getting excess
solder of the remaining hole.

A spring-loaded solder sucker may be the worst choice here
because they kick-back and can damage some of the finer
sized surface mount parts. better a pump (bulb) type or
desoldering braid or to ream it out while remelting the
solder. When in doubt, add flux... before desoldering, when
clearing the hole, and soldering in the new part. Just
don't use the water soluble stuff normally reserved for
non-electronics (plumbers flux for example), a mildly active
rosin or no-clean is far kinder to the board.

 

[Richard Brooks]

(e-mail address removed) said the following on 21/08/06 21:24:

The motherbard has to be pretty expensive to justify recapping. And,
well the ones that need recapping just aren't....... But if the
motherboard is a freebie, and you can do the work yourself, and have
the parts already, there's no reason you shouldn't do it.

I've got a Jetway 830CF that needs the electrolytics recapped and am
getting a bit pissed off with being beaten in the last few seconds by
another buyer in the eBay auctions.


Richard.

 

[xModem]

(e-mail address removed) said the following on 21/08/06 21:24:

I've got a Jetway 830CF that needs the electrolytics recapped and am
getting a bit pissed off with being beaten in the last few seconds by
another buyer in the eBay auctions.

You'd probably benefit from free eBay sniping software, or a site that offers
free sniping, eg http://www.justsnipe.com/ or
http://www.hammertap.com/hammersnipe/

 

[Richard Brooks]

xModem said the following on 21/08/06 23:04:

(e-mail address removed) said the following on 21/08/06 21:24: [snipped]

The motherbard has to be pretty expensive to justify recapping. And,
well the ones that need recapping just aren't....... But if the
motherboard is a freebie, and you can do the work yourself, and have
the parts already, there's no reason you shouldn't do it.

I've got a Jetway 830CF that needs the electrolytics recapped and am
getting a bit pissed off with being beaten in the last few seconds by
another buyer in the eBay auctions.

You'd probably benefit from free eBay sniping software, or a site that offers
free sniping, eg http://www.justsnipe.com/ or
http://www.hammertap.com/hammersnipe/

Damn! I thought it was going to be a clip of .303 and a lone rooftop
somewhere.

Thanks for those links though.


Richard.

 

[Richard Brooks]

kony said the following on 21/08/06 21:53:

Yes I do it quite often.




... and there must be some followup information here? I'll
throw out a few random comments.

It's no big deal really, not as hard as some would suggest.
I've never pulled up a trace with the cap and the random
idea some have about multi-layer boards being an issue is
nonsense, any through-board caps have plated through-board
holes that desolder same as if it wasn't a multi-layer board
(meaning only two layers, top and bottom). Surface mount
caps can be more difficult especially if positioned very
near other parts, so in that case you may need a very high
heat iron and very long tip, probably small chisel tips work
best here. As on other work, having the right sized tip
that is in good condition (clean, tinned well, and not
eroded away) can be important (or at least a lot easier).
You can make do with a sub-optimal shaped tip often but it
just depends on the exact scenario.

On some of them you'll have small signal traces very near
the cap leads so you need a steady hand and a higher heat
fine-tipped iron... also presuming some general soldering
experience and a way you're proficient at getting excess
solder of the remaining hole.

A spring-loaded solder sucker may be the worst choice here
because they kick-back and can damage some of the finer
sized surface mount parts. better a pump (bulb) type or
desoldering braid or to ream it out while remelting the
solder. When in doubt, add flux... before desoldering, when
clearing the hole, and soldering in the new part. Just
don't use the water soluble stuff normally reserved for
non-electronics (plumbers flux for example), a mildly active
rosin or no-clean is far kinder to the board.

All good stuff of course and I still have a RadioSpares pack of the fine
tips for IC work at hand. The only real difficulty at first was finding
the 1500uF electrolytics but I've found a few places.

Many thanks to all,


Richard.

 

[kony]

All good stuff of course and I still have a RadioSpares pack of the fine
tips for IC work at hand. The only real difficulty at first was finding
the 1500uF electrolytics but I've found a few places.

.... just be sure those caps are particularly low-ESR types,
as many caps on boards fail because they weren't.

There were many so-called defective caps that would pop if
just sitting, board not even plugged into a system. I
happen to have one I check on every now and then, eventually
all of the same make/model caps have swollen. On the other
hand some were just cheap, cost-cutting by the manufacturer
and fail do to being insufficient for long term service.
ESR too high, they ran warm->hot and fail.

A couple places to get caps are Nichicon UHE at
http://www.Mouser.com or Panasonic FMs at
http://www.Digikey.com. There are a few links in this post,
http://groups.google.com/group/alt.comp.hardware/msg/3ce11cdbbbbd225f

 

[WindsorFox]

Out of interest, has anyone here done simple repairs such as
electrolytic capacitor replacement on a motherboard ?

Although not a motherboard, I'd successfully done this by replacing a
single capacitor (and replaced a link) on an audio line on an old
Hauppauge WinTV card that was inside a muddy computer that had literally
been thrown out but I was wondering if anyone has done this with a
larger piece of kit ?

Richard.

I replace caps on some Biostar main boards. Total PITA and not worth
the trouble. I just definately refuse to by Biostar anymore.

--
I used to have abs. Now, I've just got ab.
One big ol' Ab. - BigSkiff www.titanspot.com

Pyongyang sounds more like the sound effect an ACME catapult makes
as it goes off at precisely the wrong moment for Wile E. Coyote. -
Cadbury Moose

 

[meow2222]

It's no big deal really, not as hard as some would suggest.
I've never pulled up a trace with the cap and the random
idea some have about multi-layer boards being an issue is
nonsense,

no, they require more care than single sided pcbs. No problem for you
or me, but for someone that has to ask if they can do it or not,
trouble can easily happen. I've seen many traces pulled off boards, and
I dont mean the old phenolic stuff. Just a case of a bit of experience
required, as ds and multilayer boards dont handle the same as single
sided.


NT

 

[kony]

no, they require more care than single sided pcbs.

"Care" being a relatively unuseful term, the procedure to do
it correctly does not change, the factor can be completely
ignored. Far more significant with the most commonly
failing caps is that what copper the plated holes are found
in, is a power plane that 'sinks away a lot of heat.

trouble can easily happen. I've seen many traces pulled off boards, and
I dont mean the old phenolic stuff. Just a case of a bit of experience
required, as ds and multilayer boards dont handle the same as single
sided.

I find it far easier to work on plated through-hole stuff
than single sided boards, especially the low quality single
sided boards seem to be the most prone to having traces
pulled up. The typical caps on motherboards will not pull
up traces when removed, because of that plated hole. That
is, except for some of the newer, more often P4 boards that
use quite a few SMT 'lytic or canned hybrid caps even for
voltage regulation subcircuits.

 

[Richard Brooks]

(e-mail address removed) said the following on 22/08/06 23:00:

no, they require more care than single sided pcbs. No problem for you
or me, but for someone that has to ask if they can do it or not,
trouble can easily happen. I've seen many traces pulled off boards, and
I dont mean the old phenolic stuff. Just a case of a bit of experience
required, as ds and multilayer boards dont handle the same as single
sided.

No problem for me either! I used to make them (including PJs 'Private
Jobs') at BBC Engineering when it existed but we pulled out when all the
multi-layered stuff came out.

I just wondered if there were any people crazy enough to do repairs in
this "sorry mate, a capacitor has gone on your larger widescreen tv and
we can't get a replacement board so best throw the whole lot into a hole
in the ground" type world we live in.

Don't laugh! Something similar to that basically happened with a large
tv I got quite new when the internal fuse went once. The second time
the bloke didn't even take the back off and told me to go back to the
insurers to write it off and get a new one. Needless to say it's been
working well for a few years since then and my mother has a free
widescreen telly.

I've even still got some old Wireless World magazines in the attic.
Should have kept the wonderful Elektor magazines though!


Richard.

 

[meow2222]

"Care" being a relatively unuseful term, the procedure to do
it correctly does not change, the factor can be completely
ignored. Far more significant with the most commonly
failing caps is that what copper the plated holes are found
in, is a power plane that 'sinks away a lot of heat.




I find it far easier to work on plated through-hole stuff
than single sided boards, especially the low quality single
sided boards seem to be the most prone to having traces
pulled up. The typical caps on motherboards will not pull
up traces when removed, because of that plated hole. That
is, except for some of the newer, more often P4 boards that
use quite a few SMT 'lytic or canned hybrid caps even for
voltage regulation subcircuits.

The difference between multilayer and ss boards is the time that heat
must be applied for before pulling, and the amount of force that can be
safely applied. A relative beginner used to working on ss boards is
liable to melt the solder on one side, wait, assume the hole must
surely be molten all the way through by now, and pull the cap, thinking
the leads are a bit bent or something hence its stiff. The result is
more comes out attached to those leads than was expected.

The other difference is f course a brute can work on ss boards and
easily repair anything pulled off, whereas that wont fly with ds or
multilayered.


NT

 

[kony]

The difference between multilayer and ss boards is the time that heat
must be applied for before pulling, and the amount of force that can be
safely applied.

Yes, it is much SAFER to apply force to a multilater board
with plated-through holes.

A relative beginner used to working on ss boards is
liable to melt the solder on one side,

No, anyone and everyone working with boards is melting the
entire plated hole's solder reservoir practically "all at
once", there is only milliseconds difference in time to heat
the entire back side till the solder has melted, and to have
all the solder in the hole melted too.

wait,

Wait for what?
You're stretching your argument pretty thin, we can equally
claim that no matter what soldering job anyone is doing, if
they "wait" after melting the solder to do anything more,
it'll be a problem. If you meant wait after having the
visible solder melted, it is never this situation. These
holes are actively sinking heat the whole time and their
entire exposed surface is covered in solder. To melt one
side, you would not be able to stop before you'd melted that
in the hole too.

assume the hole must
surely be molten all the way through by now, and pull the cap, thinking
the leads are a bit bent or something hence its stiff. The result is
more comes out attached to those leads than was expected.

Very unlikely. You can pull pretty darn hard on a cap and
end up pulling the leads out of the body of the cap before
you'd pull that soldered-in hole out, unless of course it
was extremely OVER heated, but then there's no question that
the solder had been melted all the way through.

Regardless, I've never suggested a "beginner" to soldering
should repair motherboards, nor would I suggest a beginner
repair single sided boards. It is not a factor, if one can
solder, there is nothing about multilayer boards making it a
problem. It is easier because of that plated hole, at least
to get the cap out it is, then the more difficult part is
clearing the hole of remaining solder, or rather, having the
pump to do it safely or being very careful reaming out the
hole.

The other difference is f course a brute can work on ss boards and
easily repair anything pulled off, whereas that wont fly with ds or
multilayered.

Still disagree, if someone is competent to work on either
type, they should have no problem getting through-board
leaded caps off. If they aren't competent at all, it's same
story as anything else in life, they take their chances
either way. What you have written about the problems, was
already more thought and work than actually doing it.

 

[meow2222]

On 23 Aug 2006 08:20:30 -0700, (e-mail address removed) wrote:

Yes, it is much SAFER to apply force to a multilater board
with plated-through holes.


No, anyone and everyone working with boards is melting the
entire plated hole's solder reservoir practically "all at
once", there is only milliseconds difference in time to heat
the entire back side till the solder has melted, and to have
all the solder in the hole melted too.


Wait for what?
You're stretching your argument pretty thin, we can equally
claim that no matter what soldering job anyone is doing, if
they "wait" after melting the solder to do anything more,
it'll be a problem. If you meant wait after having the
visible solder melted, it is never this situation. These
holes are actively sinking heat the whole time and their
entire exposed surface is covered in solder. To melt one
side, you would not be able to stop before you'd melted that
in the hole too.


Very unlikely. You can pull pretty darn hard on a cap and
end up pulling the leads out of the body of the cap before
you'd pull that soldered-in hole out, unless of course it
was extremely OVER heated, but then there's no question that
the solder had been melted all the way through.

Regardless, I've never suggested a "beginner" to soldering
should repair motherboards, nor would I suggest a beginner
repair single sided boards. It is not a factor, if one can
solder, there is nothing about multilayer boards making it a
problem. It is easier because of that plated hole, at least
to get the cap out it is, then the more difficult part is
clearing the hole of remaining solder, or rather, having the
pump to do it safely or being very careful reaming out the
hole.




Still disagree, if someone is competent to work on either
type, they should have no problem getting through-board
leaded caps off. If they aren't competent at all, it's same
story as anything else in life, they take their chances
either way. What you have written about the problems, was
already more thought and work than actually doing it.

Your whole post assumes that no-one else uses a lower temp iron than
you do. IRL many do, I have had a slow wait for many a multilayer hole
to melt. Muck on the tip also causes this by poor thermal conduction,
and again this is common on hobbyists' irons. Most people that ask
whether they can desolder are unlikely to be using thermostatic irons.


NT

 

[kony]

Your whole post assumes that no-one else uses a lower temp iron than
you do.

Of course, no matter what you're soldering, it'd be possible
to choose too low an iron tip temp, whether it be an iron
with only one fixed temp or an adjustable one. So the
multilayer board still has the same base requirement to
"choose right temp for the job".

That IS slightly more difficult these days with everything
being RoHS compliant now, requiring higher temp, but to put
in simplier terms- If someone wandered down to their local
Radio Shack and randomly grabbed that cheap 40W iron they
sell, it'd do the job, albeit with a little more difficulty
simply because the tip is a bit stout.

IRL many do, I have had a slow wait for many a multilayer hole
to melt.

It may depend on the size of the hole, leads for some
devices are quite a bit larger than for a motherboard cap.

Muck on the tip also causes this by poor thermal conduction,
and again this is common on hobbyists' irons. Most people that ask
whether they can desolder are unlikely to be using thermostatic irons.

Sure, a clean tip works much better... on anything, not just
multilayer boards.

It is not a difficult thing to do if one has basic soldering
skills.