Rodrik Studio which you can read on the System-CFG forum (french) (a good forum on older computers), has done four videos about 3 differents Amstrad CPC models (videos by the oldest to the more recent) :

• restoration of an Amstrad CPC 664 1/2
• restoration of an Amstrad CPC 664 2/2
• Amstrad CPC 6128 Plus restoration and discovery
• Amstrad : the CPC models (1984/1985)

He opens and cleans all machines, and also refresh the exterior of the computer with the retrobright method.