Changes
The thick black wire is 220-240V supply. The white wire is probably antennae. The other two black wires are unknown, maybe external speaker, in case it doesn't have an internal speaker?
== Service Manual ==
* [http://www.cpcwiki.eu/manuals/Amendment%20Service%20Manual.rar Amstrad CPC464-6128-GT65-CTM644-MP3-CT1 Amendment Service Manual] (pdf) (the CT1 parts list, schematic, component map are found on the last some pages)
