Unusual Altair 8800 power supply. Upgrade kit, factory error, or something else?

[Chuck Guzis]

On 11/11/2015 12:05 PM, Joseph Lang wrote:
> Rev 0 used a small (too small;-) transformer and suffered. The later
> PS used a larger transformer, but the layout had to be swapped to
> clear the card cage.

Yes, the transformer was too small.  But "card cage"?  All I've got is a 
bunch of blue plastic card guides screwed to the (4 slot) backplane PCB. 
  When did the metal card cage come into being?

--Chuck