Pretty sure it won't work, you need to use the same drive to swap them and yes you do need to keep the original logic board off your drive.
I'd just focus on getting your slim fixed.. Have you tried 3.56 v2? It's meant to fix the bug, but I haven't updated any of mine to 3.56 myself so can't say.. Besides, most games work without a laser at this stage, if you want any that don't work discless, use your original disk in your slim.
You can get a replacement laser, but they're un-predictable for how long they'll last (since most of them on Ebay are refurbs). I'd look for a YLOD 40GB and just take the drive from that, since it's an original laser it should last longer and it'll only cost you like €50 if ya hunt around, very easy to swap them too.
oralphie: Will this allow chuck norris to play backups??? PLZ HELP!!!