I took some pictures and made a rough, partial schematic of the Sega Stunner circuit board while working on a receiver for my IR light gun project. The pictures were up on Twitter but are gone now. I’m just putting a copy of the files here because they’ve helped at least one person in the past.

The Sega Stunner is a relatively simple light-gun circuit. The heavy lifting is done by a pair of ICs. The top of the board has a 74HC14N Hex inverting Schmitt trigger and a LM359N Op-AMP.

The bottom of the board has most of the other components.
 

I’ve only traced out the circuit around the 74HC14N because it’s the part that I needed. I’ll try to redraw the circuit in KiCad someday. I’ll also trace out the Op-Amp circuit. I’ll update this page when I do.  

Here’s a video of my fake stunner circuit with a Japanese Saturn.