Since that unit CAN and WILL accept multiple choices of DIFFERENT manucturers power ATX supplies, with only the plug in power connector(s) having any relation to your HP unit.
You need to be giving the paticular PS brand now being found in the unit and its Model / identification number.
Even if that power supply happens to be branded with a HP number, others would have manufactured that unit.
THEN you see how THEY chose a design to manufacture THEIR unit . . . . .with forthcoming photos probably being needed.