If you watched the last video, and if
you didn’t, it’s up here somewhere.
You’ll see me fixing one of my PCBs. It
was pretty horrible. Now, I’ve been
watching some other people on YouTube,
and hopefully in this video, you’ll see
that I’ve improved my skills. Now, all
the PCBs in this video did come from PCB
Way. There’s a link to them in the
description. They are really good, and
they’ve done lots of PCBs for me. So,
check out the link in the description
and go to PCB Way. Now the problem with
the PCBs is that I had messed up the RGB
LED. I had designed it thinking it was
common cathode, but the component is
actually common anode. Now you might
think this should be as simple as
swapping the component, but the pins do
not match up. So we have to do some
surgery. The first thing to do is to
actually remove the LED. For this, I’m
using my hot plate so I don’t melt any
of the plastic with the hot air gun. Now
with the LED removed, we need to clean
up the pads. So I’ll stick some flux on.
So, we’re a good blob of flux there. And
then we’ll use our solder wick. So,
we’ll just drop that on top. And then
come in with the soldering iron and suck
all the solder into the solder wick. So,
this works really nicely. You just need
plenty of flux and um and your soldering
iron. And that’s the pads nicely cleaned
up. So, we’ll just rub that around. And
then all the solders gone.
And we’ll just flick that out of the
way. Then we just come in with a bit of
100% IPA and clean up the surface. So
that’s looking pretty clean and nice. So
I need to cover up this ground pad. So
I’ll just dab a bit of solder resistor
on there. So try and get this fairly
thin. We want the LED to sit on top of
this. We just need to insulate this pad
so that we’re not shorting ground to
VCC.
So I’ll use my uh little um magic UV
lamp here. Run that for a minute or so.
And now we’ve got some nice solid um
solder resist on that pad. We’ll just
put some blobs of solder onto these
pads. Now, when I was doing this, I put
quite a bit of solder on. So, I just
dabbed on top just to remove some of
that solder so we’re not completely
swamping the um the LED with solder. So,
then we stick a bit more flux on so we
get a nice joint. Stick some flux on.
Then it’s back on the hot plate. And
once the solder melts, the LED will just
pop straight into place. So the um
surface tension of the melted solder
snaps it nicely into place once
everything’s melted. So we’ll give that
a bit of a bit of a weight.
And there we go. Snapped nicely into
place. And you can see the flux bubbling
away.
And then once again, it’s back in with
the 100% alcohol and we’ll clean this up
nicely. So, just get rid of all of that
flux out of the way. So, let’s do a bit
of an inspection of our handiwork. So,
just uh tilt this up and then focus in.
And uh and those joints joints, they
don’t look that great.
And uh nor does this one. It’s a bit
kind of looks a bit dry and horrible.
So, we’ll just come in with a soldering
iron and we’ll touch up these joints a
little bit. So, I’ll just give them a
quick tap with the soldering iron just
to uh reflow the solder and make it nice
again. So, a quick tap there
and a quick tap there.
So, they look quite nice now. Look not
bad. Let’s do the other side.
So, we’ll focus down and then we’ll just
come in with the soldering iron again.
just to get the angle right so I can do
this without melting the plastic.
And there we go. That’s now a nice nice
joint there. Looking pretty good. Now
it’s time for another quick clean with
IPA just to get rid of any residue from
there. Now, in the previous video, I
tried to solder the wire and then bend
it to connect it to the right places.
This was a complete pain. The joints
kept breaking and it ended up being a
bit of a mess. So, what I’ve done this
time is I pre-shaped the wire so that it
actually is the perfect shape and the
perfect length and it should connect
from pin 2 where we’ve got 3.3 volts to
the other pin of the LED and that will
complete our circuit and turn our thing
into a common anode. So, here’s where
we’re going to put it. So, it will just
line up nicely there and there. And I
bent this so that it’s pretty much
perfect. So, that’s pretty good. But
what I want to do is tin the ends of
this um enamelplated wire. So there’s a
good technique you can use to do this. I
learned this recently. So I’ve got my
soldering iron here and I’ve heated up
to just over 400°.
Going to put a blob of solder onto this.
So stick some nice solder on. And then
we’ll just feed in the ends of the
enamel wire that we want tinned. So
that’s one end done. Just leave it in
for a couple of seconds and that works
really nicely. It burns off the enamel
and you got nicely tinned wire to go
back onto your PCB. So, we’ll stick that
back down.
So, that’s back into position. Just
maneuver it so it’s in the right place.
This just pretty awkward. Um, it’s quite
hard maneuvering underneath the
microscope, but there we go. So, that’s
in approximately the right place. And
what I’m going to do is I’m going to
stick that down using captain tape. So,
we’ve got our captain tape stuck to the
wire. So, we’ll just push this into the
right position. Again, this is quite
awkward. The uh the tweezers often stick
to these tiny bits of wire and pull them
off the PCB. So, we just push that down
so that it sticks nicely. And now that’s
nicely secured in pretty much the right
position. We can just maneuver it
slightly to get it perfect.
So, there we go. Stick that down.
And now we’re in a good position to
actually solder these two ends of the
wires up. So, I’ll just push it so it’s
in the right place.
And that’s looking pretty good to me.
So, move that wire up slightly. Make
sure it is really stuck down. And now I
can just come in with a bit of flux. So,
we put flux on that end and some more
flux on the other end.
And now straight in with the soldering
iron and a bit of solder. And that’s one
one end done. And then straight to the
other end. Go there. And now that’s
nicely nicely hooked up. So we have a
really nice joint there. It’s nice and
neat. Much better than my previous one.
Now, let’s just beep it out to make sure
it is actually connected. So, that’s
really good. We got our nicely soldered
up piece of wire. Looks pretty neat.
It’s not that long kind of crazy bit of
wire that I had last time. So, we just
remove the captain tape. Now, we just
need to clean up all the residue flux.
Now, this is where I made a small
mistake. I was a bit too vigorous with
the cleaning with my toothbrush and IPA.
I did slightly dislodge the wire and
bend it out of shape slightly, but I
managed to get it back into a reasonable
thing. Now, we’re just going to cover it
up with some more solder resist. Um,
this started off okay, but then I went a
bit crazy with the solder resist and got
way too much on the paintbrush and um
put a massive blob on. So, this started
off looking pretty good and pretty kind
of a nice thin layer that would stick it
down to the PCB.
And then um this happened. So I got a
much too much a massive blob of solder
resist. Um it’s fine because it does it
does actually set. Okay. But that is way
too much. So not ideal. And I dribbled a
bit over the LED. So my nice repair
turned into slightly less of a nice
repair. But the wires all there and it
actually works. So the LED is now
flashing nicely. So, that’s fixed our
issue with the LED. Got quite a nice
repair, especially compared to my
previous effort that was a bit bonkers
and had a massive piece of wire going
all over the