PowerMac G4 doesn't display anything after noise tweak..

[tfcata]

It's nice to see a forum about PPC macs that's still alive..

I have bought a old PowerMac G4 MDD a while ago and it's probably the windtunnel. It's working fine. Recently, I'm trying to reduce the fan noise so I bought another PSU with the Samsung label and replaced the fans in it.

Problem is after I put the PSU back in the MDD doesn't display anything. It does turn on. I hear the chime, hard disk spins up and does a bit of the seek noise. Then there's no display on the screen. The USB port seems to be powered coz I can turn on the Caps Lock LED the keyboard, but the LED seems to work only around the time the hard disk is spinnin up. Then the keyboard does not respond anymore.

I've tried resetting the NVRAM and taking out the PRAM battery.

I've not tried the PSU with its original fans coz one of those are broken during shipping. So I'm not sure it's working in the first place. The old PSU has been working fine, though.

Any idea? Thanks.

 

[Dronecatcher]

The MDD model is prone to much inexplicable weirdness - especially re the PSU.

Have you tried removing the graphic card then re-seating it?

 

[tfcata]

I just tried re-seating the graphics card, same problem.

I tried removing the ram sticks, too.

Any more ideas? What I'm thinking of trying next is maybe replacing the fans in the original PSU, since it seems this MDD is really picky about PSUs...