Circuitry is all germanium
semiconductor with a pair of Mullard OC35 power transistors feeding
the output. For a change the thing looks like it was designed
to comfortably meet its 30 volt, 1 amp output rating. Some modern
power supplies are a fraction of this size butneed a blower to
keep them cool. The blue-coloured thing in the centre is a full-wave
bridge rectifier. It smells of selenium but the four devices
on brackets look like GEC germanium diodes and "GEX541"
is written on the assembly. In keeping with the weighty transformer
these diodes are rated at 80V and 10Amps.