Unsoldering battery

[Orange]

I have to unsolder NiCd battery ("barrel" type) from motherboard. It
isn't reachable from solder side, only from battery side. Can it be
done? How many watts are required?

 

[Dr. Anton Squeegee]

I have to unsolder NiCd battery ("barrel" type) from motherboard. It
isn't reachable from solder side, only from battery side. Can it be
done? How many watts are required?

Best choice there is to use diagonal cutters to get rid of the
battery itself, and then desolder the pieces of lug that remain in the
holes.

A standard 30-watt or so Weller pencil will do just fine. Tip
temperature should be about 700 degrees F. Use solder-wick to clean out
the holes once the lugs are gone, and use 99% Isopropanol and a small
stiff brush to clean the flux residue away before you install the
replacement battery.

 

[Orange]

Best choice there is to use diagonal cutters to get rid of the
battery itself, and then desolder the pieces of lug that remain in the
holes.

Could you explain me what are diagonal cutters (my english is poor)?
How do they differ from ordinary cutters?

A standard 30-watt or so Weller pencil will do just fine. Tip
temperature should be about 700 degrees F. Use solder-wick to clean out
the holes once the lugs are gone, and use 99% Isopropanol and a small
stiff brush to clean the flux residue away before you install the
replacement battery.

Thanks.
What is solder-wick?
I'm worried that heat might damage motherboard. For how long should
solder be used?

 

[Peter Bennett]

Could you explain me what are diagonal cutters (my english is poor)?
How do they differ from ordinary cutters?

In my world, diagonal cutters _are_ "ordinary" cutters - they are
perhaps called "diagonal" because the cutting blades are at an angle
of 30 degrees or so to the plane of the handles. There are also end
cutters, where the blades are close to 90 degrees to the handles.

Thanks.
What is solder-wick?

Solder wick is a copper braid that is impregnated with flux. When held
on a solder joint and heated, it will (usually) suck up most of the
solder, allowing the pin to be removed from the board without damage.

I'm worried that heat might damage motherboard. For how long should
solder be used?

To

 

[Dr. Anton Squeegee]

Could you explain me what are diagonal cutters (my english is poor)?
How do they differ from ordinary cutters?

Difference in terminology, most likely. They're often called
'diagonal' or 'dikes' here in the States for the simple reason that the
blades slant at about 30 degrees or so.

Thanks.
What is solder-wick?

Available from most electronic supply stores, it consists of a
small circular package containing fine-mesh copper braid that's been
treated with flux. When held against a solder joint with a hot soldering
iron, it will (usually) have the effect of wicking enough solder out of
the hole for any leads present to be removed without damage to the board
itself.

I'm worried that heat might damage motherboard. For how long should
solder be used?

No more than 20-25 seconds, I would say. Make sure the iron's tip
is clean, and tin it slightly before you go after the joint. You should,
ideally, be working on the board (or any other modern circuit board) on
an anti-static surface.

Good luck.

 

[JeffM]

Bruce gets it right again!

The rule is:
Sacrifice (cut out / cut up) whatever you have to (components)
to save the expensive / hard-to-get stuff (PWB).

Once the big thing (component) is out of the way
(with its thermal mass / hard-to-navigate-around body / etc.),
what is left (usually pins or wire stubs) comes out more easily
with minimal damage to the board.
(e.g., severing all the legs of a bad chip
--unsoldering and pulling one pin at a time is much easier than all-at-once.)