Tutorial DIY Mod ANY PSU to power your PC HP 590 

ANY Watt Power Supply Upgrade for the HP 590 series
Follow this guide and find out how to swap any powersupply into any HP 590 series
HP PSU Proprietary work around was pretty basic.
This is my sunflower hahaha MOBO
STEP 1
In order for the proper functioning of the new PSU we need to jump the Green Signal On wire to a ground.
STEP 2
Determine the mandatory wires you will need
Mandatory wires to motherboard:
4 Wires 12v + Yellow
4 Wires 12v - Black ground
Optional wires to motherboard:
Grey power ok
Green signal On
Black ground
Final Note
In order to completely Power Off the unit I first Shutdown the Computer. Then use a Switch on an Extension Cord to cut power entirely Saving more money in the long run.
The switch is optional can always just Unplug after Shutdown
HP 400 watt PSU L04618-800
Hard to find