XFX Radeon 5870 and Tagan TG600-U33 PSU: black screen

[runeks]

Hello Hexus forums

I'm experiencing problems getting an XFX Radeon 5870 graphics card to work with a Tagan TG600-U33 power supply and a Gigabyte GA-EP35C-DS3R motherboard. When I plug in my monitor and start it up, the fans start spinning and all, but the screen remains black. I know the graphics card works properly, it starts up fine in my other computer that has a FSP ZEN400 PSU and an Abit IP35 Pro XE mobo.

The reason I think it might be the PSU is because I've read on other forums, that changing the PSU helped. But I just can't understand why this would be the issue. This PSU is rated for 20A on each of the four 12V rails, and I'm connecting it to the 12V3 and 12V4 rails as far as I can tell, using the blue 6 pin PCI-E connector and the 6 pin orange PCI-E connector (not using the extra 2 pins on this one). Which looks like this:



In the manual it looks like these two connectors should be able to provide the card with 40A:

http://www.tagan.com.tw/page/datashe...00_uk_mini.pdf

Is this not sufficient? My other FSP Zen400 PSU is (according to the manual) only able to provide 14A+13A=27A and it works fine with the card.

Does anyone have some suggestions as to what I might try? I've tried putting a Sapphire Radeon 5770 (which has only a single 6 pin PCIe connector) card into the PC in which the 5870 doesn't work, and it works fine.

Any ideas on what could be the issue?

[Phage]

Dead 2nd PCIE cable ?

[runeks]

I can run a 5770 (which requires only one connector) with either the blue or the orange connector. So that seems to not be the case.

I did notice something odd though, I got an electric shock when I touched the PC case earlier. Not anything serious but I could feel it quite clearly. It's running now with the 5770 in it, and I can touch the case fine now without feeling anything though, so I'm not sure what that was all about.

[Phage]

Sounds like a bad earth connection somewhere. A live case is very bad. Can you swap another PSU to check ?

[runeks]

Sounds like a bad earth connection somewhere. A live case is very bad. Can you swap another PSU to check ?

I might be able to bring home another PSU tomorrow. I'll report back if I make any progress.