If I was you, I'll toss away those underpowered original PSUs and use this hack instead:

Here is the external view:

Where:
Preto = Black
Vermelho = Red
Marrom = Brown
Amarelo* = Yellow
Branco = White
* The guy who makes this make a BAD mistake. He puts the shield on the +5V line.
Instead of this, put the yellow wire (shield) on ground (with the black wire). Do not put the shield wire in anything else (like the PSU ground itself).
Any old peecee AT-PSU works.
Just one more tip: peecees PSUs must have the "power good" (PG on the board) wired to +5V line in order to properly work.