
also, this ebay auction is bugging me.
( ,
Sun 3 Oct 2010, 0:16,
archived)

that's a power supply unit and TV modulator for an Amstrad CPC464 (possibly the 664 and 6128 too). They were bespoke units for Amstrad hardware. I find it highly unlikely they're in any way compatible with the C64 or Vic20.
( ,
Sun 3 Oct 2010, 1:19,
archived)

Works for me.
( ,
Sun 3 Oct 2010, 0:17,
archived)