Please Help me figure out what I'm messing up!

[trickymickey]

Ok I might be a total noob, but I can't figure out wtf is wrong. I ordered all my parts and started putting together my computer. Everything seemed to be going well, I got the cpu and heatsink installed on the mobo no problem, installed the mobo in the case seemingly lined up properly, installed the power supply in the case. I figured I was 80% done and just need to plug in power, video card, ram, etc. I go to plug in my PCI cards and they don't line up with the back of the case, and to be able to screw in my PCI cards, I have to flex the mobo quite a significant amount.

Is there any chance the case/mobo are not compatible, i didn't think this was possible. I've checked to make sure cables are out of the way, the offsets are all screwed in hand tight and appear to be flush. I even checked the case to make sure it was level, it is. Parts list is below, any suggestions are welcome.

Thanks!

Antec 900 Case
AMD Phenom II X4 955 Black Edition
ASUS M4A79T Deluxe AM3 DDR3 AMD 790FX
Corsair 750TX 750W
SAPPHIRE 100259-1GL Radeon HD 4870 1GB 256-bit GDDR5
Western Digital Caviar Black WD6401AALS 640GB 7200 RPM 32MB Cache SATA
3.0Gb/s 3.5"
Samsung SH-223F DVD Burner
OCZ Platinum 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800)

 

[hunter315]

Did you line all 9 of the mounting holes? They should line up perfectly, that motherboard fit great into an antec 300, however the top expansion slot is not used and does not line up with a slot on the board in the antec 300 it likely occurs in the 900 as well so dont try to line it up with the top slot. Just double check that you put the standoffs in all the right spots and that the backplate is flush with the back of the case and everything should line up.

 

[trickymickey]

The connectors at the back seem a little off, and the mouse/keyboard ports seem like they're higher than they should be... not sure what would be cause that as the mobo seems screwed as far down as it can be, but there appears to be a small gap. Should I just take out the standout, this seems like a bad idea since it's a corner standout.

 

[hunter315]

No the standoffs are incredibly important, did you replace the back panel that came with the case with the one that came with the motherboard? Make sure you pop the cover all the way into the spot on the back of the case.

 

[trickymickey]

Yes, I did replace the back panel with the one that came with the mobo, the ports seem to line up except for the ps2 mouse/keyboards. Is there a way to post a picture on here to show what it looks like?

 

[Paperdoc]

Maybe try doing it in a different order. Loosen the screws that hold down the mobo - in fact, take then right out. For this, obviously, you should have the case lying down so the mobo is horizontal and gravity is holding it in place. Note carefully where you have ALL the standoffs installed, just in case you get to deciding that some have to be moved.

Now, with the mobo free to move, try to align it so that the custom rear panel and all its ports line up exactly and fit into the rear opening snugly. Check that the PCI slots line up with the rear openings, maybe by temporarily installing a PCI card. NOW is when you go around and see if all the screw holes are lined up with standoffs. If there's one wrong, move it. If they are all lined up, put the screws in until they are NOT tight, then check the alignment with the case again. When it's right, tighten down the mobo mounting screws.

 

[trickymickey]

I acutally did something quite similar to this. I matched up the holes but did not screw it in, then connected the graphics card and screwed it into the rear of the case. The I/O panel on the back was pretty close, however, when I tried to screw it in although the standoffs were underneath the holes, the board was not lying flat on them towards the front of the case, so then if I try to tighten them down it flexes the board, not a ton, but considerably more than I'm comfortable with. It's as if I don't have the graphics card all the way pushed in and so it's not perpendicular to mobo, except that is not the case (I even took the board out with the gcard in to check that it was all the way in).