Powermac 5400/180 Help

How long did you leave it on before you decided it wasn't going t o do anything? Sometimes they'll take a good 30 seconds before they kick in and start loading, activate the screen, etc.

What exactly is the problem? Is there just a black screen?

There was a 5400 at my old school that I got a while back because the monitor apparently didn't work; I plugged in an external monitor (mirrored image, not second screen) and for some reason, the internal display decided to work again out of nowhere. Macs like to do things like that

What are the specific symptoms you're getting? What exactly is "nothing" when you say "nothing happened"?

I rescued a powermac 5400/180 from a certin grave thie is my first Macintosh. When I plugged it in I her the monitor power up with a soft boongg. Then nothing happend. I had a known good motherboard from a friend. I tried that and the smae thing happend. Are there any common fixes or has anybody had this problem before?

Try pressing the CUDA switch on the logic board for 20 seconds if you didn't when installing the logic board.
Leave it on longer as mentioned and if nothing happens you need to get a boot disk. Get an OS install CD or floppy and try to start with the boot disk in the Mac. This should get the 5400 running if there is a bad HDD or corrupted OS on the HDD. If everything on the board is known to be good I would think it's the monitor. If the 5400 has the external monitor plug you can try that, or add a PCI video card from a working Mac and try an external monitor to get video. If that doesn't work then you probably have a dead monitor or video board.

...sounds just like a 5400 to me. Mine went 'dead' like that just after I got my old 6500, so it was no real loss; but 2 months later when I lugged inside and powered it up to see if I could find out what was wrong, well, nothing was wrong. Started up like a real trooper. So in summary, there's no real 'fix' for that as such, any number of things might work- including a good kick.