Board Thread:Questions and answers/@comment-35306464-20200410131139/@comment-30049823-20200410185513

There aren't any Nerf blasters or accessories with an actual laser, so I assume you're talking about an LED focused through a plastic lens (e.g. Nite_Finder_EX-3_Sight) or REALLY old-school conventional light bulb (e.g. Eagle_Eye)

In either case, it's most likely just dead batteries (replace 'em) or corroded terminals (clean 'em), followed by a broken wire (resolder it), and lastly a dead bulb.

If an LED bulb is dead, you either already know how to unsolder/remove/replace it, and wouldn't need to be asking this question -- OR you don't already know, in which case the best course of action is to find a working one at a thrift store and demolish the old one for parts.

The exception would be something "rare" like a Deploy_CS-6_(Whiteout), which is semi-rare and worth enough to bother diagnosing and fixing the wiring or replacing the bulb.

That's as much "speculative" help as I'm able to give; you'll need to make your question a lot more specific if you want an actual answer.