From the description by sickmods.net, there seems to be an err in the Delta 1.6 PSU diagram.
They mention that the white wire on the PSU connector in standby (STB) is at 0V and when you press the power button to turn on the Xbox this signal has 3.3V applied to it which goes to the power supply to turn it on. Then the blue line is to have 3.3V on it once the PSU is stable. But, the diagram shows there's 3.3V on the blue lead in both STB and ON conditions which contradicts their description. It states that there is only a 5V STB voltage (orange) no 3.3V STB with a v1.6 PSU so why is 3.3V listed in STB for the blue lead?
White is PowON signal and blue is PowOK. PowOK (blue) should not be OK (3.3V STB) until the power supply is stable; therefore, PowOK (blue lead) so should be 0V in STB until after the PSU has been signalled to turn on by application of 3.3V to PowOn (white wire).

- Updated Xbox v1.6 Delta PSU STB voltage level based on operational description at sickmods.net
I've not measured the STB and ON voltage levels at pin 10 - PowOK (blue) to verify this change.