If you want some more insight into soldering that thing down, I can offer my experience (yeah, I've soldered stuff like that). The process is generally very time consuming and tedious, but tends to work well. If that's the 0.5mm pitch, that's the toughest kind, but they're doable.
A temp controlled iron with a decent tip is a must for this, but you don't need to go incredibly fancy and get a top of the line Metcal. Hot air helps, but isn't required. I use a Weller WESD-51. Set your temp reasonably. You want it hot enough to flow solder rather quickly, but not so hot that you're burning the board up. I usually stick to between 300-350C.
Getting the old chip off is easy. Just take a sharp knife and shear all the pins off of the package, being very careful not to cut into the board itself. Then take your iron and "wipe" the leads off the pads. Be careful that you let the lead/pad warm up before applying any lateral pressure, otherwise you'll tear the pad off the board (and that is not easily repaired at all). I've had good luck intentionally getting the leads to stick to my iron, then wiping the iron on the sponge to remove the leads.
To solder down chips like that, I generally flux the row of pads and drag solder, then clean up the excess flux and use solder wick to remove bridges. Basically, you apply flux to the bare board along all the pads not worrying much about where it goes since the soldermask will usually keep most of the solder in the right place. Position the chip (this is BY FAR the hardest part) and tack down the corners. Then you get a SMALL "blob" (just a little drop) on your iron and drag it gently along the very edge of the lead/pad interface. The flux will suck the solder in and form the joint. With a little practice, you can get the angle on your tip and your drag speed just right so that you won't form too many bridges. You'll have to back off and apply some more solder to your iron tip frequently (the people who are really good at this can feed the solder in as they drag).
You'll have some bridges, so clean up with solderwick, then use either flux remover or simple rubbing alcohol to remove the excess flux (there will be tons) before it dries. A visual inspection (possibly with extensive magnification) for bridges is usually more effective than attempting to electrically test.
1-0.8mm pitch is really easy with this method, but 0.5mm pitch can get a bit tough. If you want, you can also try reflowing, but you'd need a stencil to get the solderpaste on cleanly enough to prevent bridges. Reflowing does make positioning easier as the surface tension of the solder/flux tends to help center the chip on the pads.
Suffice to say, if you have trouble soldering big stuff, this probably isn't even worth trying - get somebody else to do it. If you mess up, you'll likely destroy the board and/or chip in the process.
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Topic: looking for someone that repairs arcade boards (Read 5068 times)
