--- In
DW8000@yahoogroups.com, Shayne Cafferata <scafferata@s...> wrote:
> i was desoldering one of the voltage
> converters and i ended up lifting the copper pads, all three of them.
> shit! i'm using a push-pump desolderer and it is just not doing it for
> me. someone recommended desoldering braid. is there a specific kind that
> works well?
> i've tried some stuff from radio shack and i thought it sucked.
> is there a cure for what i've done? or is it time to start looking for
> another pwr supply board?
Lifting copper pads from the voltage regulator isn't the end of the world. Here's my
advice, coming from a long background in electronics repair:
Push pump desolder tools are very useful to get rid of the excess solder on contacts, but
it's really just a first step. You should then do detail desoldering using a soldering iron
and copper desoldering braid. Any brand should do as long as the copper is shiny, rather
than oxidized. If you are not getting good results with Radio Shack desoldering braid,
(which is generally quite good, although more expensive when you go through quantities
of the stuff) also purchase a tube of electronics soldering flux, which Radio Shack also
sells. Wipe desoldering flux on the copper desoldering braid before using it, and you'll be
amazed at how the stuff just sucks up solder.
For your detached voltage regulator pads, (presuming they are completely broken,
detached from everything) you'd generally accomplish a repair like this: Find the circuit
trace that the pad was connected to, and carefully scrape away the (usually) green coating
with an Xacto knife to reveal fresh copper. Apply a dab of fresh solder to it with a
soldering iron. Get some reasonably sized wire, preferably solid, and solder one end to
the solder dab, wrap the other end around the pin of the regulator that it goes to, and hit
it with solder. You can use rubber insulated wire if you need to bridge some length.
Alternatively, follow the trace that the pad was connected to until it hits another
component connected to the same trace. Use an iron to lift that component's pin a bit,
and then use a new piece of rubber-insulated wire to tack-solder one end to that
component, then wrap the other end around the regulator's pin and hit it with solder. For
long wire runs, if you want to be really neat and tidy, you can tack a couple dabs of
silicone sealant or hot glue every couple inches along the wire's length to keep it in place
on the board.
Note that if it's a wide trace you're repairing this way, you should use a reasonably thick
wire. Power supply circuit traces are often wide to accomodate large currents, and you
don't want to be splice-repairing it with ultra-thin wire, which will act as a fuse!
-Mark