A dead Toshiba TA7357P sync separator IC was killing the chroma output on a Sony BVW-75 Betacam SP VTR. The chip is obsolete and unobtainable. Without it, the deck output no color except in paused mode with dynamic tracking off, producing only odd color stripes.
Engineer ldursw reverse-engineered a fix using a available substitute IC that had three problems: wrong footprint, wrong voltage, and inverted output. The solution was a small PCB combining a voltage regulator, an inverter, and a video amplifier chip, all arranged to match the original TA7357P pin-for-pin as a drop-in replacement. The breadboard-to-PCB process and the specific component choices are documented in full on GitHub.
The full schematic and board files are open source at github.com/ldursw/ta7357p. The repair method is the reason to read this one, not just the outcome. Anyone archiving Betacam SP footage on original hardware needs to know this exists, and the broader approach of wrapping a modern substitute in a compatibility shim applies well beyond this single IC.
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