The metal plates appear to be heat sinks to disipate the heat on the bridge rectifier (although this is hard to confirm for sure from these photos).  Basicly it looks like the transformer simply steps down the voltage from 240vAC to 6 or 12v dependant on the setting of the front switch.  It would then pass through the bridge rectifier to be made into direct current (DC) output.

IT maynot be the transformer that is faulty, you need to have this tested by someone with electrical knowlage whom can use a multi meter etc.  Is there any fuses on the unit?  It may be that you have output from the transformer and that the bridge rectifier is stuffed.