There is probably a pot on the laser that you can try to adjust. Tiny turns and retest. I think I have a spare Dreamcast I'd let go if you're looking for another.
I've tried the pot, I didn't try too long, though. I still have my original Dreamcast, this is the one I got in the lot I posted about a week or two ago so it isn't too bad considering what I payed. It would have been nice to have a backup or trad bait, though, instead of a paper weight.