Wannien 101v0 Power Supply Schematic Review

Within a month, three other repairs were done in Manila, Mexico City, and rural Kentucky. All because a girl in Saigon learned that a schematic isn’t a treasure map—it’s a conversation across time, signed in solder and stubborn love.

Old Mr. Hà, who’d repaired American tank radios during the war, squinted. “Wannien? Ah. Copy of a Lambda LK-350. But they swapped the feedback loop. Look for a 4.7k ohm resistor near the optocoupler.”

She took a photo of her cardboard schematic and posted it in that old Reddit thread. Subject line: Wannien 101v0 Power Supply Schematic

The voltage rose unsteadily, then locked at 13.8V. Steady as a heartbeat.

Inside: a landscape of scorched copper traces, four swollen electrolytic capacitors (their tops bulging like tiny volcanoes), a cracked TO-220 transistor (label: ), and a resistor so blackened it looked like a piece of charcoal. A puzzle with missing pieces. Within a month, three other repairs were done

Linh sat back on the tile floor, listening to the ghost signal, and realized: she hadn’t needed the original schematic. She needed the courage to trace the dead circuit herself, ask the old men, and trust her father’s half-finished notes.

She spread the components on a newspaper, took a photo, and visited the three old men who still squatted on plastic stools outside the market, drinking iced coffee and arguing about capacitors. Hà, who’d repaired American tank radios during the

She’d searched. Oh, how she’d searched. The model was obscure—a short-lived Taiwanese clone of a Japanese linear supply from the late ‘80s. Wannien Electric Co. had gone bankrupt in 1994. No PDFs. No forum archives. No grainy scan on a Russian electronics site. Just dead links and a single Reddit post: “Anyone got the 101v0 diagram? Mine went pop. Help?” No replies.

Linh had no formal training. She had nimble fingers from untangling earbud cords for tourists and a stubborn streak inherited from a man who once fixed a 1967 Ford ambulance with a coconut shell and prayer. But she didn’t have the one thing the internet insisted she needed: .

She rebuilt the schematic herself on a torn piece of cardboard: transformer → bridge rectifier → filter caps → 2N3055 pass transistor → LM723 control IC (she’d found one hiding under a heatsink) → feedback divider. A clumsy drawing, but hers .

She added a note: “He never finished drawing it. I finished it for him.”