soldering to IC pins....(help!)

[jamiewoody]

i am struggling with this. the solder does not seem to want to stick to one of these.

what could i be doing wrong? advice please?

[Gordonjcp]

You need quite a hot soldering iron, and you need to get the pin hot enough for the solder to melt properly to it.  The problem is, if you do this close to the IC package you can damage it...

When you solder something the surface needs to be clean, which is why solder has flux - it helps clean contamination off the surface.  You could try a wee spot of liquid flux, such as you'd use for soldering surface-mount parts.  It's important that the solder "wets" the part that you're trying to solder to.  You might get the solder to "stick" but it will break away if it hasn't wetted properly.  Look at the difference between raindrops on a freshly-polished car, and raindrops on a less shiny surface - on the polished surface it's a mobile "blob" which sits on top, but if the water "wets" the thing the surface tension is broken and it "sticks" to the surface.

[jamiewoody]

as far is this goes, i discovered 2 things. first, i was tinning my wires before soldering, which seems to be the normal practice.

i found (2nd thing) if i play "hooky" with my wires, then solder that helpes. if i tinned the wire first, it would not fit around the IC pin.

the things that sucks, as you mentioned, i think i may have fried the chip. no sound, just light static if you listen closely to the tiny speaker.

the thing i love about the bigger SK and MT series casios, is the larger circuit boards, and bigger solder dots, so  it is not even nessesary to solder to the IC itself. *sigh*.

note taken though, gordon. cleanliness is next to godliness. i need to get a big ole' can o' contact cleaner. that stuff is not cheap these days either!

it seems like an odd combo, extra hot soldering iron, but too much heat will fry the chip. it would take the wisdom of galolph the grey to know this delicate balance! 

[Circuitbenders]

it seems like an odd combo, extra hot soldering iron, but too much heat will fry the chip. it would take the wisdom of galolph the grey to know this delicate balance! 

be quick

and practice on something that doesn't matter.

[nochtanseenspecht]

if it is too hard to do, better solder to the connected traces on the board.. no risk of heating the ic

[jamiewoody]

the hard thing is i don't think there were traces on the sa2.

[jamiewoody]

i finally conquered this! see the other thread of a similar title...

[electoyd]

Jamie

here is the advice i put on the other thread, may be helpful for you, easy now

ian

sounds like your making this tricky for yourself   I would say always use leaded solder, it runs better than unleaded (but please take precautions if you use this).  Get a thin wire (i use rainbow wire which is a flat strip of about 20 coloured wires and thin).  When soldering directly to an ic (a non surface mount) make sure the wire is well tinned with no big blobs hanging off, get a pair of tweezers (you can get ones with a wooden handle so they dont heat up) pick the wire up with the tweezers and hold it to the bottom of the ic pin (where it is soldered to board) and then very quickly apply fresh solder to iron and touch lightly where you want to solder.  Quite often i would go round the pins on the ic that i wanted to solder to and add a small blob of fresh solder so that it would be easier to add the wire later.  Under no circumstances would i ever use single core wire for bends, it is next to useless for this as it always breaks.

If you get a solder bridge the best thing you can use is servisol copper braid or soldamop as it might be known, i would only use servisol as have used others and they dont work (though you may be tempted by their cheapness).  Soldamop works by touching the braid next to the solder you want removed and heating it with the solder iron and it just soaks into the braid, wonder stuff great for removing components as well.   I have never had any luck with solder suckers.

[jamiewoody]

i'm down with everything you say, electoyd. i do like making a small "hook" with the SC wire though. however, that and making small jumpers is all solid core wire is good for. a  year ago, i was drawn to SC wire because it does solder easy, etc. but, it is definitely a no-no for hooking things up which need to flex.

[Ciderfeks]

The telephone exchange box near my house always has longish off-cuts of sc wire left laying around by untidy telephone engineers.     Its good for making breadboard jumper cables and also for repairing pcb traces, as well as the other uses discussed in this thread.

[Gordonjcp]

Inside telephone exchanges they have huge rolls of that blue-and-yellow twisted pair stuff.  When you get a line connected, it's used to patch across from where your pair comes in to the switch port terminals on the MDF.  Miles and miles of it, all blue-and-yellow.  Bloody hard to track down.

The pairs up CAT5 premise cable is about the same size.  CAT5 patch leads are multistrand and not suitable, but premise cable is single-core.

[jamiewoody]

i am always looking for free hookup wire. lol! my neighbor gave me a cable for an old car cellphone hookup (i think). i am still using that wire!