soldering ICs to prepunched circuit board

[Ed]

Hello all, I've purchased a piece of circuit board from Radio Shack, and
am having a hard time soldering an IC (ULN2068B motor driver) chip to
it. The rest of the circuit is passive, and that's not a problem. It's
not my soldering skills. I'm guessing that the momentary heat is
killing the IC. Radio Shack makes some IC 'sockets' which you can
first solder on, then insert the chip... but the pins are < 1/4" long,
and once through the plastic board, there's no 'meat' to work with. Any
suggestions?

Thanks,
Ed

 

[John Popelish]

Hello all, I've purchased a piece of circuit board from Radio Shack, and
am having a hard time soldering an IC (ULN2068B motor driver) chip to
it. The rest of the circuit is passive, and that's not a problem. It's
not my soldering skills. I'm guessing that the momentary heat is
killing the IC. Radio Shack makes some IC 'sockets' which you can
first solder on, then insert the chip... but the pins are < 1/4" long,
and once through the plastic board, there's no 'meat' to work with. Any
suggestions?

As long as the socket pins are visible in the holes, you should be
able to solder them in place. What would you do with longer pins,
except cut them off after soldering? The trick is to hold the socket
in place somehow, till you solder two opposite corner pins to hold it
in place while you solder the others.

 

[Garrett Mace]

As long as the socket pins are visible in the holes, you should be
able to solder them in place. What would you do with longer pins,
except cut them off after soldering? The trick is to hold the socket
in place somehow, till you solder two opposite corner pins to hold it
in place while you solder the others.

somehow == masking tape

 

[Steve]

I just slightly bend the pins on opposite corners to hold them in place
until I can get some solder on them and the rest..

Steve

 

[John Popelish]

John Popelish wrote: (snip)

somehow == masking tape

I usually solder all sockets in first, with the board laying flat on
top of them. Otherwise, I put some small object on the table that
will prop the board up slightly through pressure on the socket till I
get it tacked down.

 

[Garrett Mace]

somehow == masking tape

I usually solder all sockets in first, with the board laying flat on
top of them. Otherwise, I put some small object on the table that
will prop the board up slightly through pressure on the socket till I
get it tacked down.

Unnecessarily difficult. If you don't have enough sockets to make a stable
setup, at some point you tip the board with the soldering iron or your
finger and everything falls out. Or, if you have lots of sockets, you have
to hold everything in with fingers and do some sleight-of-hand to get it all
on the tabletop in one piece. I messed around with that tactic for a while,
and found that a simple strap of masking tape across the socket lets you
solder all of them at once, and clamp the board in a vise where it's not
going to flip or skitter across the table at the slightest nudge. It also is
a good way to immobilize SMD parts before you get those first few critical
pins tacked down.

 

[Rich Webb]

Hello all, I've purchased a piece of circuit board from Radio Shack, and
am having a hard time soldering an IC (ULN2068B motor driver) chip to
it. The rest of the circuit is passive, and that's not a problem. It's
not my soldering skills. I'm guessing that the momentary heat is
killing the IC.

Did you thoroughly clean the board before you started soldering? The
solder core helps some, by reacting with the oxide layer, but it's hard
to get a good "wetting" action on copper oxide and so you may be having
to leave the iron against the chip for too long. It's not like soldering
to a tin-plated pad. Try some fine (1600, 2000) grit wet/dry sandpaper
in water. Polish until it shines and then dry with a lint-free wipe.

 

[Ed]

Thanks for the reply. I guess I mis-stated my problem - I'm trying to
solder a piece of wire onto the bottom of the lead. Maybe I'm a bad
solderer, but I can't get the wire to make a good enough physical
contact with the pin that I feel comfortable tacking it down with a bit
of solder.

Basically, I have the socket on top of the board, then underneath, a
small lead of wire wrapped around one of the pins, which I then solder
for permanence. Then the other end of the wire lead goes to a
transistor, etc.

How do y'all attach wires to the sockets?

*John Popelish* uttered the words:

 

[Rileyesi]

Thanks for the reply. I guess I mis-stated my problem - I'm trying to
solder a piece of wire onto the bottom of the lead. Maybe I'm a bad
solderer, but I can't get the wire to make a good enough physical
contact with the pin that I feel comfortable tacking it down with a bit
of solder.

Basically, I have the socket on top of the board, then underneath, a
small lead of wire wrapped around one of the pins, which I then solder
for permanence. Then the other end of the wire lead goes to a
transistor, etc.

How do y'all attach wires to the sockets?

This may help (or may not!)

There are two types of IC sockets: a solder type and a wire wrap type. The
solder type of sockets have short pins that are designed to go through a PBC
like the pins of an IC would. They stick out of the solder side of the PCB
just enought to let you solder them in place. These are typically used in PCBs
that have traces or some type of copper on them.

The wire wrap type has longer pins that sitck out farther from the PCB enabling
you to wrap a wire to them using a tool called a (now get this!) a wire wrap
tool! When used correctly, and with the correct wire (which is very thin), you
can "stitch" todether a circuit using a board called a punch board or a perf
board. This is a board that usually has no copper on it at all. You put your
resistors, caps, diodes, IC sockets, etc. into the perf board and then make the
circuit connections using a wire wrap tool and the correct wire.

The wire for this is thin. I bought a wire wrap tool and a pack of three
colors of wire (the colors come in handy when de-bugging the circuit) from
Radio Shack for a total of about $12.

If done correctly, the wire wrap technique needs no solder.

Hope this helps.

 

[Fritz Oppliger]

Thanks for the reply. I guess I mis-stated my problem - I'm trying to
solder a piece of wire onto the bottom of the lead. Maybe I'm a bad
solderer, but I can't get the wire to make a good enough physical
contact with the pin that I feel comfortable tacking it down with a bit
of solder.

Basically, I have the socket on top of the board, then underneath, a
small lead of wire wrapped around one of the pins, which I then solder
for permanence. Then the other end of the wire lead goes to a
transistor, etc.

How do y'all attach wires to the sockets?

Those circuit boards are pretty cheesy - the holes are fairly large and
the pads will lift off if heated only a little too much.

assuming that every part is CLEAN...
The trick is to heat the pad and the pin and the wire at the same time.
Maybe your wire is kinda big ?
Make sure the wire is pre-tinned. You can try to hook the wire around the
pin. Or, before soldering, stick it into the hole alongside the pin. THis
will help the solder to wick into the hole.

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