Elitedesk 800 G4 Tower - PSU Upgrade

[tj2388]

Hello,

So I'd like to install a new GPU (RX 6600) into my Elitedesk 800 G4 Tower.

I thought I picked out the correct 500W PSU (L77487-001) to replace the stock 250W PSU (L08417-002) and properly power the GPU, but when I put in the new PSU (without touching the GPU) I got no video output. The CPU, case fan, and Wi-Fi card all came on, however, and the PC beeped once. I've reinstalled the 250W PSU and the PC is working without issue, so at least I didn't fry anything.

Current GPU is an NVIDIA Quadro P400, if that's relevant at all.

I noticed that the new PSU's PWRCMD connector only has 3 wires (green, gray, and black), while the old PSU has all 7 wires. Is that known to cause any problems?

Maybe I have to change a BIOS setting? I changed a setting there a while ago that's caused the video output to be delayed on startup, essentially locking me out of the BIOS screen unless I do a CMOS reset, from what I've read. If that's the case, then all I have to do to perform a CMOS reset is to press the CMOS button on the motherboard, correct?

Thanks for any answers, I know I've asked a lot of questions.

[NonSequitur777]

@tj2388,

Welcome to our HP Community forum!

Yes, the 7-pin "P2" config does make a difference.  I've got quite a bit of experience with the HP EliteDesk 800 G3/4/5 platforms.  Go with the 500-watt p/n: 901759-013 which has all 7-pin P2 wires, such as this eBay purchase example: 500W PSU Power Supply Unit For HP Envy 795-0003UR Desktop L05757-800 901759-013 | eBay.

[EDIT:] Or go with this less expensive 500-watt p/n: L77487-001 (6-wires P2 is OK too) such as this eBay purchase example: HP Z2 G4/G5 SFF 500W Desktop Power Supply - OEM - L77487-001 PA-5501-2HA | eBay.

Kind Regards,

NonSequitur777