Pictures of Dragon power source boards to help with identification.
Issue 4 (P/N 48256, 250x85mm) :
The green cable and open track on the solder side seem to be an official fix, as other 64's have it too and it's consistent with the schematics. Maybe a Dragon 32 to Dragon 64 upgrade?
Type CT (UK Dragon 32 with Serial No. 019193 DG)
Square, type CT
Type TD64-1 (Dragon Tano)