Have an HPz200, replaced standard 320 PSU with EVGA 850 BQ and now the system won't startup

[smgrubb]

This is the PC in question: https://support.hp.com/us-en/document/c02027649

16GB Ram

Intel Core i3-540 3.06 GHz, 73 W, 4MB cache, 1333 memory, Dual-Core, HT

320w PSU

Came with AMD firepro GPU but I will be replacing that with a bit newer model.

It was working before I decided to try and give the system a little extra oomph.

Mainly I just wanted to put in a new gpu, probably try to upgrade the cpu a little later.

I took out the older 320w PSU, and I happened to have an EVGA 850w BQ semi-modular psu on hand. Got it fit in there and connected it to the Sata CD drive and HDD, connected the cpu cable, connected the motherboard cable, and connected the GPU vga cable. Nothing happens when you try to turn it on.

No lights up front, no fans spinning, no green light on mobo. Nothing.

I have tried replacing ram and/or leaving one stick in.

Replaced CMOS battery.

Tested PSU.

Checked wiring from power button to panel on mobo.

Unplugged everything but the mobo and cpu.

The only difference I can see, is that on the 20+4 pin connector from the PSU, there are no connectors in the 20th hole. Whereas the old PSU that I took out does have something in the 20th hole. Is that the issue? Is there anyway to use this PSU? The man reason is that the new gpu requires 6pin vga cable to power it (whereas the firepro did not) and the old PSU does not have a 6 pin vga cable and it is not modular.

[DGroves]

the hp z2xx series workstations do not use a standard ATX power supply they use a custom supply with a 20 pin connector

instead of the 24 pin one. also the voltages on each pin does not follow the ATX standard

also note that the HD SATA power comes off of the motherboard using a 4 pin to sata cable as i recall

the reasion it will not turn on is because you are applying the wrong voltages to the motherboard pins and  causing a direct short to the system. the power supply is detecting the short and engaging the self protection shutdown circuits

connecting the wrong supply can damage both the motherboard and the power supply

you may be able to make or buy a power adapter harness that reroutes the pins to the order the motherboard expects

i would check the HP service manual which lists the pinout and see if the 200/210/240 systems use the same pinouts

then search ebay for a adapter

https://www.ebay.com/itm/HP-Workstation-Z200-ATX-PSU-Adapter-ATX-to-HP-Proprietary-Power-Connector-C...