| Using desoldering braid
the better way. I will do this
in the best way, which may be longer but better, and normally cleaner
and ultimately tidier and less risky.
firstly the bad bit.
Carefully remove the mainboard, make sure
you have patience, and note where all the screws came from organising
them in such a way that you can remember what length of screw came from
where, more damage is done by people putting the wrong screws back in
the wrong place than anything else.
Above you can see a standard dc socket
and the normal damage that occurs at the same time.
In most of these cases people only get
round to replacing the socket when they can no longer charge the battery
or power the system, and when sending it in for repair they always say
it was only the dc socket, nothing else.
this is rarely true, when the socket goes
it normally damages something else at the same time, as you can see by
the tow copper bound components behind the socket in this case they have
been damaged.
in this case this will probably be ok.
but always be aware of this type of damage, and that if the copper had
been broken of the board, this would have had to have been soldered back
on also, (or the components repaired, or replaced)
In many instances the PCB itself will
have been damaged, this is not difficult to repair as long as you can
trace an non damaged part of the board before components that the socket
can then be wired to. (ask in this case and i will explain, (if i don't
yet have that tutorial written)
Firstly clean any dust or dirt from
around the connection
Shown above is the next step and is
important.
The main aim to get a clean job is to get
the solder to run free and easy, the best way to do this is to add some
extra flux, here i am applying a little extra flux with a flux pen, an
nice easy clean and economical way to do this. (a flux pen will do
hunreds of jobs)
Next you will need a clean well tinned
iron, use the tip cleaner and tinner to clean the tip, and then wipe
afterwards, on the sponge (damp) supplied with your iron, this will
leave a clean well tinned tip.
Next is the bit that see odd, but
helps, (when solder has been on a joint for a long time, it sometimes
gets brittle, corroded, and will not flow easily) so.
Resolder the old joint, making the solder
on the old broken connector fresh, and will flow easily with the extra
flux applied earlier.
Now use some fresh desoldering braid and
push it down tigtly on the solder joint with your iron, the old solder
should happily run into the braid and out of the joint, it will flow to
the hottest part of the joint, so as the soldering iron is on the other
side of the braid than the connector, it will flow from the connector
down the braid away from the joint.
Now you can see the joint, with the
connector removed, add a tiny amount of flux, then wipe with the tape
wrapped round the solder tip, this will clean of any residue.
Now put the new connector on the board,
as you can see here, i have slightly bent the pins to hold the connector
into place while it is being soldered
Now run a little solder into each joint.
Then use a little flux remover on a brush
to clean up the board contacts after being soldered, this will leave a
good wet joint that will last as long as the connector.
Note you should of course remove all of
the flux as most of them are mildly or more corrosive, and are not good
for the pcb's
|
Using a
vacuum pump
- Using a vacuum pump below
example
of the pins on a dc connector or component
using a suction-type desoldering pump, apply the soldering iron tip first to
melt the solder joint (say for 1-2 seconds). Ensure the spring-loaded
desoldering pump is 'primed' and ready to go
The
PTFE nozzle of the desoldering pump is applied to the molten solder and the
spring-loaded plunger is then immediately released, drawing the molten solder up
into the pump. Remove the soldering iron tip. Repeat the process if needed.
If you are having proble sometimes it helps to add some
fresh solder and then desolder the whole joint.
The
first pcb. joint, now desoldered
using
traditional desoldering braid.
Select
a suitable width of desoldering braid, and press it down onto the
COLD joint using the hot tip of the iron. A flat soldering iron bit is
preferable.
The
molten solder is drawn up by capillary action into the desoldering braid. Take
care not to overheat the board (the pcb. copper track may lift off), nor 'drag
whiskers' of solder over the board, nor let the braid solidify onto the joint!
Remove the braid while the joint is still molten.
The
faulty electrolytic capacitor dropped out of the board after desoldering.
Sometimes, it may need persuading with pliers.... but
don't overdo this or you risk damaging the copper tracks on the pcb.
Close-up
photograph of both joints, now desoldered and ready for the replacement
component to be fitted.
Clean up the holes, where the connector fell out, with tape
(hold the tape down on the holes with a hot soldering iron.
fit the replacement socket/jack into the holes, and solder
back on with a clean soldering iron.
done.
|
Locate your dc socket
on the mainboard:
Pull back any metal
shield or retaining spring out of the way first
