How can I test the Max Amps a PSU can pull?
Look at the label under output, most have the rates max output on them for each voltage line...
How can I test the Max Amps a PSU can pull?
The metal frame is being used as a heat sink.
Bob
Correct, except the rectified 120V will be more like 170V. The peak voltage of a sine wave is sqrt(2) times the RMS voltage, and a bridge rectifier with smoothing capacitors will produce something close to the peak voltage when not loaded.120V AC enters a Bridge Rectifier that turns the AC in DC 120v (or 400v?), then Switched to 20Khz(ish) before it Inters a Transformer, Go inter a Voltage Regulator, then Gets Smoothed By Capacitors. And now you have say 12v Rail?