atx supply wont start

What's the open-circuit voltage on the green wire? What's the voltage on the "always-on" 5V wire? Forget what color it is. I assume you've disconnected the 20-pin plug and the 4-pin processor 12V plug and the disk drive plugs and the video card plug to isolate shorts.

probing the disconnected plug-green and red(5v) both 0 volts!

Grounding the green pin won't do anything if there's no voltage to begin with.

The "always-on 5V" ain't red It's purple.

I have seen many P/S that do not conform to the color code.

all 0v strange

And I have seen PSUs (Dell !) that don't even comply with the pinout code :-)

Not strange..."BROKE". You ain't gonna get nowhere until you get some volts on the green wire.

Google is your friend, befriend google. atx "power supply" schematic

=D0=DA=E0=D8=F8 =DD=D0=D2=D5=D4=D5=DD=D8 =E2=D5=DA=E1=E2 -

update double checked purple and green both 5v,yellow~0.5v and the rest

The green must be connected to COM before the supply starts. The purple is just a always on and it seems it's working. Just connect the green to black, and put a small load on one of lets say one of the RED wires (5 Volts).

The loading is very important, the PS won't stay on for more than a few seconds without a load. When I use a standalone PS I hang an old disk drive on it.

Open up your PSU & look for a blown fuse.

checked diodes and resistors with power off-ok,capacitors visually look ok. when you connect green to ground the fan starts spinning briefly (1/10sec), is there a generic 300-400w atx schematic someplace because google-ing as "Rexpower" did not help

ta delenda est

You might not be providing enough of a load. Try attaching an old hard disk to it.

Not that I know of.

None of the schematics at the google search string I suggested?

atx "power supply" schematic