A third independent Japanese build, by someone who now runs x86lab.jp as a small retro-PC and electronics business. He made his own logic board (silkscreened “DRSSTC Logic Board v1.0”, with a universal prototyping area left open on purpose “so the cause is easier to track down”) and a separate integrated gate-drive-and-full-bridge power board, with Mitsubishi IGBT modules. The write-up keeps the failures in. The gate driver let out smoke on first power-up, then an IGBT failed, then the CT’s input resistor blackened from heat. Each one was diagnosed and fixed in public. One fix, removing the freewheeling diodes entirely and relying on the IGBTs’ built-in ones, came directly out of one of these failures. The project ran from September 2021 to 2022.
Schematics and photos
power board PCB layout
Sources
This is the card from the driver tree, written from what the builder published. Send corrections through the forum.