Hi, I have a G4 Z4 Xeon MB and I amgoing to figure out wether it is working or not. I do not have the Z4 PSU therefore I have to decode the 18 pin and the 12 pin PW connector pinouts to be able to connect an ATX PSU. I have some experience in HW troubleshooting feel free to ask.
What measured so far. Name the 18 pin PW MB connector's pins as the previous post's Z400 PW connector. Pin 1 is left side pin next to the memory slots, Pin 10 is the oposite pin to Pin 1.
The possible GND points are:
on the right side: P17, P16, P15
on the left side: P4, P5, P8
On the 12 pin PW connector (CPU MEM PWR):
Pin1 top of the pin next to memory slot, Pin 7 is the opposite one to Pin 1, next to the MB PCB.
The possible GND points are:
on the right side: P7, P9, P10, P11, P12
I am asking Alisha to measure with the multimeter the other pin's voltages referencing the ground pins as follows in order to determine wether the PSU is OK or not. It is easy to measure. Do not forget to mirror the pin numbering from the PSU mother connector.
# In normal cases when the PSU is powered but not connected to the MB than the PS_STBY, PS_GOOD and PS_ON pins should be present as 5V. There should not be 12V on any other pin. Please try to find which pins have 5V. If there are two or three of them than it is OK. Please connect the 18 pin PW connector to the MB. Put the MM positive probe into the back of the connector of the PSU to one of the pin showing 5V the other probe to Ground and press the power button. If the 5V drops to near zero than that pin is the PS_ON pin and the other one having 5V is the PS_OK or PS_STBY. I would appreciate if you could give me these two-three pin's numbers.
# Please disconnect the PSU from the MB. You have the PS_ON pin and the GNDs. I suggest to use an 1kohm resistor and some wire to make a connection between the PS_ON and GND. In this way you can start the PSU without the MB. Measure the voltage on the other pins. There should be 12V and 5V present on multiple pins. If the PSU is in disassembled state yet than I ask a favor: please check the cables of the 5V from the connector to the PCB of the PSU: You will see one of the 5V cable is not going to big puffer capacitors. That 5V cable is the PS_GOOD signal cable. Please share the Pin number.
# Maybe some pin has no voltage "floating pins" at all. It is not a problem, document these pins please. Later on the voltage should be tested again with connected MB on these pins.
# If the 12V, 5V are present in "standalone" mode that remove the jumpstart wire, connect the PSU to MB, push the power button and measure the voltages of the PSU connector's back. It should be 12V, 5V on the same pins as you measured standalone and maybe 5V on some of the "floating" pins. Please document these voltages-pins as well if any.
# Please do the same measurements on the 12 pin PW connector as well and share the measurement results.
# That is it for the first round to figure out the state of the PSU. Any comment is welcome, let use-test this beauty MB. I am more than happy to help you to diagnose your board because I have to do the same with mine!