Upgrading PSU and Graphics card in Dell Optiplex 790

[emattrick1]

I'm trying to upgrade a friends graphics card and PSU in this refurbished Dell Optiplex 790.

Using a thermaltake 600W smart power supply, and a Radeon HD 6850 graphics card.

I installed the power supply, plugged everything in, and then the graphics card right after. There wasn't a whole lot to plug in from the power supply because the computer isn't very 'special'. The only connectors I saw from the previous power supply was the main power source to the mobo, power supplies to the hdd and disk drive, and then to the graphics card.

Once everything was all plugged in, I tried turning the computer on and got a single orange light flash on the power button. Followed by the diagnostic lights on the front of the computer flashing 1 &3 and then 1 & 4 I think. I tried looking at the diagnostics page for this model but couldn't make anything of it.

Does anyone see anything I am missing? Or is there a chance the new components aren't compatible with the Optiplex 790?


Thanks

 

[Dark Lord of Tech]

CPU power plugged in from the PSU?

 

[william p]

Try page 65 here.
http://downloads.dell.com/manuals/all-products/esuprt_desktop/esuprt_optiplex_desktop/optiplex-790_owner%27s%20manual_en-us.pdf
You might need to change some BIOS settings to run an older Legacy BIOS GPU, but it should work. Secure Boot is one thing that would have to go.
The warning lights make me think there is a hardware problem.
BUT did you create a System Restore point, and remove the old GPU drivers in Safe Mode (F8). Then install the GPU and load new drivers either first, or in Safe Mode?
I would get running with the old GPU. See if you have a PSU related issue, and then install the GPU as above. You made 2 changes at once ( I do it all the time) but when it goes wrong you need to back track.