No power on reassembled pc

[pikachu]

Hi!

My name is Pikachu and I am a newbie to this forum. This is my first post, so please be gentle . I have a pc that needed to switch to a new case. So I unplugged all the connections, moved everything over to the new case, connected all the cables back as well as the power supply connectors, but now the system will not power up or anything (fans, led's, nada). The reason I had to transfer to the new case was because the power switch in the old case broke and instead of getting a new switch I got a new case with a new power supply. The only difference that I see that might be a problem is the power supply watts. The old one was 250W and the new one is 350W. Could that be the cause? I don't believe so but I need input from more experienced techies.

This is my first reassembly, so any input you can give me and/or a great suggestion on literature material (book) will be GREATLY appreciated. Thanks in advance.

[Toaster]

Howdy,
There are a number of "typical" errors folks make when assembling systems.
Chief of these errors is reversed IDE cables. Most systems will not post with reversed IDE cables.
Another common error is mounting the system board incorrectly.
Many cases require "stand-offs" of some sorts and I have seem folks simply "screw" the system board to the case floor. This can damage the system board beyond repair as it shorts the system board to the case floor.
Other errors are too numerous to mention.
Another possibility is an "under utilised" power supply.
Try installing the orginal supply as a test.
Often, if the add-on cards poorly line up with the card cage, this is an indication that the system board was incorrectly mounted.
It would be helpful if you were more specific as to the system board type and other installed goodies.

BTW, Welcome to the 'Mech!

[morriswindgate]

ANother problem, believe it or not, is something simple like the ATX connector on the board not being plugged in all the way or in you case it might ba something as simple as the new power supply has a off/on switch on the power supply and the old one didn't.

[Cricket]

Hi pikachu,

Here's the link to the "Build Your Own PC" tutorial: http://www.pcmech.com/byopc/index.htm

Cricket

[BFD Deadeye]

This is also possible, and easy to overlook. Maybe you have the power switch plug on the wrong prongs on the Motherboard. When you have 2 rows of 6 or 8 pins that close together, it can trick the eyes (especially when you hit your 30's ).

[pikachu]

Thank you all for your input. It seems there are a couple things I did wrong. The first thing is that it looks like I might've shorted the motherboard because the board is touching the inside of the case (AAARGH! Dunce cap for me!). Also, what BFD Deadeye said is another problem I noticed. You see, in the old case the Power LED plug has the positive and neg prongs next to each other and the new one has them apart on the cable. I will try to show with a visual example:

old case
Power LED cable

1 2 3
P P

New case
Power LED cable

1 2 3
P P<-in 3 instead of 2

I have checked all the cables to make sure the were plugged in properly and in the right space. The things I mentioned above were the only things I saw that were abnormal. I will keep this post open to let you know my results. Thanks again.