Prototype USB-C Power Adapter — Sega Game Gear or Nintendo Game Boy (Working Seconds)

Working dongles, rough around the edges, cheap

While developing my USB-C power adapter line, I built a run of prototypes I’d always intended to sell — then kept refining the design before full production. What’s left is a limited batch of those earlier units, and they’re up here at a steep discount.

Here’s the honest pitch: these are electrically identical to the production version — same trigger/passthrough circuit, same output voltage, every one tested and confirmed working before it ships. What’s different is the finish. Instead of the production unit’s custom 3D-printed enclosure, a prototype might be wrapped in heatshrink, housed in an early case rendering, or have a straight barrel jack instead of the right-angle one. No two are quite alike.

If you want a tidy, finished adapter, buy the production version — it’s linked in “similar items” below. But if you just need working power on the cheap — for bench testing, troubleshooting, a travel/backup unit, or a project where looks don’t matter — this is the best deal I offer.

Functionally, each prototype is identical to the corresponding Lite version — same board, same output, same electrical design. Only the cosmetic finish differs.

You receive one working prototype — looks will vary

Important: you’ll get one (1) tested, working unit, and it may look different from the photos. Because each prototype was built a little differently, the pictures are representative of the product, not the exact item you’ll receive. Every unit does the same job; the cosmetics are the luck of the draw.

Pick your console

Choose from the dropdown:

• Sega Game Gear (9V) — a prototype of my Game Gear adapter. It outputs 9V through a USB-C Power Delivery (PD) trigger, so you must power it from a 9V-capable USB-C PD wall charger or battery bank (a plain 5V USB port or “dumb” cable won’t work). A small LED lights when it’s receiving 9V. Also powers the Sega Genesis 2, 32X, Nomad, and Sega CD2 (center-positive barrel).
• Nintendo Game Boy DMG (5V) — a prototype of my original Game Boy (DMG-01) adapter. It’s a straight 5V passthrough, so it runs on any 5V USB port — no USB-PD required. The simple, cheapest way to power a DMG.

Pricing

$10 each, or two for $15 (mix or match consoles), plus calculated shipping. These normally sell for $20+ in their finished form — this is the prototype discount.

What’s included

• One (1) tested, working prototype adapter in your chosen console flavor.
• Not included: a USB-C power brick, a USB-C cable, or any console. (The Game Gear version specifically needs a 9V-capable USB-C PD source.)

About the maker

I’m an electrical engineer and long-time hobbyist with a passion for vintage electronics, especially classic video games. These prototypes are from my own workshop bench. Every unit is guaranteed working on arrival. Questions are always welcome — thanks for looking.