WCIF Soldering Lessons or Services

I have recently started learning FPGA design and programming. I have a board I am happy with right now, but I need to solder some cables on it and the hard truth is I suck at soldering. Seeing how this board is expensive and imported from America, I would like to find someone to either do the soldering for me or to teach me how to solder properly.

Any takers? :slight_smile:

A cable should be ok, they are usually on big pins with wide spaces. I’ll give you some tips for smaller components, and then if you get the principle your cable should be a breeze.

Use a good quality soldering iron and good quality solder, also know at which point on your soldering iron the solder melts, (it wont melt everywhere) and keep it clean. Also have something for removing solder, I have one of these solder suckers, but can’t remember the last time I used it, some sort of wire wool that absorbs solder is great. I found an image, this is superb stuff.

Ok, so most pcb’s are covered in tiny SMD type devices, diodes,capacitors, resistors. Which are pretty ok, you take your soldering iron, (making sure its clean), place it on once side of the pad to warm it up, then bring in the solder (just a little) and it will flow and form a little blob, a small blob, you dont want too much and remove the solder. The using tweezers, pick your tiny SMD part and warm the solder with the other hand using the iron, and slide the part in. Done, then just apply solder to the other side.

Some packages, like Eeproms and Op Amps, have more than two pads, but still ok, just do like above, on one pin, maybe the bottom left or top right, and slide your part in. Then just go round and solder the remaining pins, warm the junction, bring the wire to the solder and it will flow.

Now, for some tricky parts, I used to have one IC 144 pins in about 1 inch square. This is tricky, and by hand its not possible to do each pad without it shorting the next. So, you dont need to worry. Basically short them all together, then use the wire wool I have an image off above to absorb the solder, what remains is a part that has all pins correctly soldered to the board, with no shorts.

Let me know if you need more help. Now if you have a BGA type package, (pins on the bottom of the chip, and actually looks like the one the guy in the picture is cleaning) like some of your FPGA type chips like, I wont even attempt that.

If you don’t mind me asking, is this board an FPGA development kit? Which one?

Thank you Mick for the advice. :notworthy:

msee04, yes, it’s a development kit. I bought the Xylo-EM board from KNJN.

http://www.knjn.com/shop.html?pg=pic&src=ShopItemsPics/Board_Xylo-EM.jpg&title=The%20Xylo-EM%20board

I can show you how to solder for the price of a couple of beers, but getting good at it simply requires practice and good equipment. Mick’s advice is good stuff. Follow it to the letter and you’ll be fine.

Your best bet, really, is to just practice with some junk (unloaded) PCBs. I can mail you some of these if you like, plus some useless SMT components.

If you have a shit soldering iron (95% of the soldering irons I’ve seen in Taiwan’s electronics shops fit my definition of “shit”) you won’t be able to make a good joint however hard you try. Spend at least NT$5000 and get one with a nice fine tip and an adjustable thermostat. As Mick says, even that won’t be any good for soldering fine-pitch packages (at least not lead-by-lead - I use the same method as him), but it will be just fine for ordinary work (thru-hole wires and SMT parts down to 0603). Also, it’ll make soldering fun and easy instead of a chore.

FWIW, I supported myself through part of my undergrad working graveyard shift in a Dell factory doing fine-pitch surface mount soldering under a microscope (or under a mag-ring light if it was something simple)

I guess you could say there is a trick to soldering fine pitch surface mount components. It comes down to having clean components, the right temperature, a soldering tip with the right curve and technique (practice). With the right conditions you can slide that curved soldering tip along the edge of a row of finepitch connectors in a single pass, feeding it solder as you go and the surface tension of the liquid solder will wick it up on the individual leads and away from each the others… leaving you with a row of clean, shiny solder joints and no shorts. Wrong shaped tip, go too slow, feed the solder too fast or do it at the wrong temp and youre left with a blob of solder, shorts, solder peaks etc.