A small and defunct laser pointer emerged from the back of the workbench. There being no way to repair the thing, I filed a slit in the soft aluminum case and peeled it back to extract the guts:
The corrosion on the spring adequately explains the “defunct” situation; that’s the – terminal for a trio of LR44 watch batteries. The + terminal is the glossy (aluminum flashed?) molded shape with the threads, which friction-jams into the outer tube with a tiny spur for “good” contact.
Hotwiring a power supply to the appropriate terminals shows that the laser still works fine, even if the contacts are shot.
The ribbed gray plastic ring on the business end of the laser adjusts a focusing lens. Behind that lies a cylindrical lens that corrects the beam’s astigmatism. It was a nice pointer, back in the day … and might work its way into an art project, if I ever get finished with the practical stuff.
The Smell of Molten Projects in the Morning 