Just FYI i posted there. Why use a psu that is less powerful than a A500 original? Following the guide there you will build a weak psu like A600/1200 came with. see my post there for other concerns.
+5v should be at least 4.5amps to match the original psu,and more if u have a heavily expanded 500.
The original A500 PSU not 4,5A 5VDC, 2,5A only.
The PSU not T-40B, RT-50B, 5V 4A, 12V 2A, -12V 0,5A. Look:
http://www.meanwell.com/mw_search/RT-50/RT-50-spec.pdfThis OK. The RT-65B too strong, too expensive, 5V 5A, 12V 2,8A, -12V 0,5A.
I use only a simple side expansion controller, and CPU slot fastRAM.