Computer totally freezing after a few min

elektroda.net NewsGroups Forum Index - Electronic for beginners - Computer totally freezing after a few min

Goto page Previous 1, 2

whit3rd
Guest

Fri Jan 15, 2010 10:06 pm

On Jan 15, 4:44 am, "Michael A. Terrell" <mike.terr...@earthlink.net>
wrote:

Quote:

Don't worry about desoldering. Just pull the old caps. Then use a small
drill to clean out the holes.

That is a great way to destroy the plated through holes.

True.

The big capacitors that failed are probably in plated-through holes,
meaning
that there are two wires that go into a hole in the board, which is
soldered
along its full length, with a little blob (fillet) of solder on the
non-component
side. As M.T. indicated, the solder joint COULD pull internal board
layers
apart if you just 'pull' the old caps.

So, you have to crush the capacitors, removing the bulky component
except for those soldered wires. Then, clean, flux, and gently remove
one wire at a time. It sometimes requires two soldering irons to get
this
kind of joint up to temperature, one on each side of the board;
removing
the capacitor body gives you the extra access to do that.

Solder braid may remove enough solder to loosen the wire, but if it
doesn't come loose, ADD fresh solder to the joint; the old solder
may have dissolved copper and taken on a high melting point,
the fresh solder will get it back to normal loose-when-hot
consistency. When the wires are out, use braid or a vacuum
desoldering tool to open the hole fully (more flux might help).
When all the capacitors are out, and all the holes clear,
stuff the new components in, solder, and clean up the flux.

bw
Guest

Fri Jan 15, 2010 11:32 pm

Quote:

Don't worry about desoldering. Just pull the old caps. Then use a small
drill to clean out the holes.

That is a great way to destroy the plated through holes.

krw
Guest

Sat Jan 16, 2010 1:04 am

On Fri, 15 Jan 2010 16:32:58 -0600, "bw" <bwegher_at_hotmail.com> wrote:

Quote:

"whit3rd" <whit3rd_at_gmail.com> wrote in message
news:d4b301c2-a286-46be-a49a-ac5f075a6900_at_o3g2000vbo.googlegroups.com...
On Jan 15, 4:44 am, "Michael A. Terrell" <mike.terr...@earthlink.net
wrote:

Don't worry about desoldering. Just pull the old caps. Then use a small
drill to clean out the holes.

That is a great way to destroy the plated through holes.

True.

The big capacitors that failed are probably in plated-through holes,
meaning
that there are two wires that go into a hole in the board, which is
soldered
along its full length, with a little blob (fillet) of solder on the
non-component
side. As M.T. indicated, the solder joint COULD pull internal board
layers
apart if you just 'pull' the old caps.

At least 50 caps replaced on PC boards with Zero problems. It's easy.

It's also easy to damage a board. A better solution is to heat up the
pad an poke a cold resistor lead, or some such, through the hole. This
will clear the solder without damaging the barrel.

Quote:

Obviously the drill diam. is less than the original lead diam.
I've been hand soldering electronics 40 years.

That just means you may have a lot of experience doing things wrong.
Wink

Baron
Guest

Sat Jan 16, 2010 4:57 pm

bw Inscribed thus:

Quote:

I haven't pulled the board yet to look. Do you think the cap
connection will go all the way through and be accessible from the
bottom of the board? Do you recommend using a desoldering pump,
desolder braid, or just heating and pulling the old cap out. Then to
clean the hole to insert the new part what is the best practice?

If you do it properly the hole will be cleaned by the vacuum pump.

Quote:

Don't worry about desoldering. Just pull the old caps. Then use a
small drill to clean out the holes.
I use a dremel drill with a micro-chuck.

Fastest way to destroy a plated through hole !

Quote:

Place the new cap, then solder with plenty of heat to wick the fresh
solder fully into the joint.

--
Best Regards:
Baron.

T
Guest

Sat Jan 16, 2010 8:48 pm

In article <dg02l5l8jgsmc37tf3vcdbeoih81qpfpj0_at_4ax.com>,
krw_at_att.bizzzzzzzzzzz says...

Quote:

On Fri, 15 Jan 2010 16:32:58 -0600, "bw" <bwegher_at_hotmail.com> wrote:

"whit3rd" <whit3rd_at_gmail.com> wrote in message
news:d4b301c2-a286-46be-a49a-ac5f075a6900_at_o3g2000vbo.googlegroups.com...
On Jan 15, 4:44 am, "Michael A. Terrell" <mike.terr...@earthlink.net
wrote:

Don't worry about desoldering. Just pull the old caps. Then use a small
drill to clean out the holes.

That is a great way to destroy the plated through holes.

True.

The big capacitors that failed are probably in plated-through holes,
meaning
that there are two wires that go into a hole in the board, which is
soldered
along its full length, with a little blob (fillet) of solder on the
non-component
side. As M.T. indicated, the solder joint COULD pull internal board
layers
apart if you just 'pull' the old caps.

At least 50 caps replaced on PC boards with Zero problems. It's easy.

It's also easy to damage a board. A better solution is to heat up the
pad an poke a cold resistor lead, or some such, through the hole. This
will clear the solder without damaging the barrel.

Yes, or pull a clean length of stripped 26 gauge copper wire through it.

Guest

Tue Jan 19, 2010 12:17 am

On Jan 14, 4:34 am, "Ray" <N...@NE.nothing> wrote:

Quote:

I haven't pulled the board yet to look. Do you think the cap
connection will
go all the way through and be accessible from the bottom of the
board? Do
you recommend using a desoldering pump, desolder braid, or just
heating and
pulling the old cap out. Then to clean the hole to insert the new
part what
is the best practice?

The leads go all the way through and the inside of the hole is plated
to attach to traces on each of 4 (or more) layers. Some guy calling
himself 'bw' says just pull of the caps and re-drill the holes.He's
flat out wrong if he's serious and not particularly funny if he isn't.
If you're rich, a Metcal soldering / desoldering system would be just
the ticket. Less better off a Metcal soldering iron and an Edsyn
Soldapullt can do amazingly well. Still less well off a Weller
temperature controlled iron (I prefer the magnastat units) and the
Edsyn can do well. I wouldn't try it with non-temp controlled irons.
Regardless of what 'bw' says, do NOT use drills. The Metcal STTC-126
tip is excellent for cleaning out even the most stubborn hole. Point
the tip into the hole (it may take a second or 2 to heat it) pull back
a hair and 'vacuum' it with the Edsyn. I've done it thousands of
times. While Mike Terrell may have had bad experiences with eBay, I
bought 8 Metcal systems there with no problems.

G²

T
Guest

Sat Feb 06, 2010 6:30 pm

In article <SumdnQxm5eWLAtHWnZ2dnUVZ_hOdnZ2d_at_earthlink.com>,
N_at_NE.nothing says...

Quote:

I have a few year old computer (clone, I built with VIA chipset) that has
suddenly started to completely freeze.
The image stays on the screen but the computer is completely frozen. CTRL
ALT DEL does nothing and even a reset via the reset button just brings up a
black screen (no BIOS text, no beeps, nothing).

If I power down completely Windows will boot and the system works for a
while (5 min to a hour tops) and then freezes again.

The computer has a removable drive and I have tried it with several
different boot drives. They all freeze so I know it is not a software
problem. I actually have 5 drives that I use for different tasks which is
one of the reasons I would rather repair this few year old computer rather
than getting a new one (the thought of installing & configuring 5 OS's ...).

I opened the PC and reseated all the cards & RAM. Cleaned all the fans and
heat sinks.
Have tried a different video card and removed all but one stick of RAM.

Pretty much the only components I have not eliminated is the power supply,
motherboard and CPU.

Does this sound like a PS issue to anyone?

Also 3 of the larger caps on the motherboard near the CPU have the slightest
of buldges (very little, but they are not flat like the others). My guess is
that these 3 caps are what is causing the problem, but I would like to hear
from the experts.

If you guys think it is the caps Im pretty good with a soldering iron. Is
this something that is replaceable? Do these traces usually go all the way
through the board. I dont want to remove everything yet, will do this as a
last resort especially if it sounds like the problem is the caps.

Thanks

Check your CPU fan. This sounds like a hardware fault.

Another thing you can do is to boot into safe mode. On any windows
computer just keep hitting the F8 key while you're booting and it'll
present a menu with a bunch of options. Choose Safe Mode and see if your
system stays up for more than five minutes. If it does you've found
software that is causing the lockup since Safe Mode doesn't run any
system or startup items.

Goto page Previous 1, 2

elektroda.net NewsGroups Forum Index - Electronic for beginners - Computer totally freezing after a few min