Aren't RSODs typically a result of a problem with the chip? If you were getting DREs then it would be the laser, but I guess it doesn't hurt to try.
Remove the top cover of your PS2 and take the shield off of the DVD drive. The laser lens should be exposed then clean it with alcohol/q-tip.
"Nagi, how do you feel about being 'normal'? Normal means that if you leave something alone, it just remains that way forever. So if you can't stand that, then you have to be "not normal" in some area... - Seiichi Kirima's dying words