Replaced mobo and PSU, still no-go.

[crashisme]

This is my first posting after reading great info on this forum for a long time; hopefully someone can help me better than emachines tech support. I have an emachines T2792. I'm a mac video guy but needed something simple for internet and word. I've had this machine for almost 3 years. Recently, the computer shut down out of the blue. Wouldn't power up at all. After doing some research, I decided to purchase a new power supply (350W upgrade). Installed it...no power still. Did more research and found out the MoBo goes when the PSU goes many times. Purchased a used MoBo on Ebay (the person claimed to have tested it working fine). Installed new MoBo and now I turn on the power switch in the back, fans comeon, yellow led in the front, and that's about all that happens. I hit the switch in the front (do you have to do this with the new switch in the back) and I get nothing. Almost forgot, I am getting power to the monitor. Any ideas?

[JANINE]

You have some power which is a good thing. You have power to the LEDS and to your monitor and fans. This leads me to believe that either your motherboard isn't all its cranked up to be and possibly the main motherboard connector may be damaged or there is a fault in your power supply unit. You need to ideally test the mainboard connector on your power supply and the easiest way to do this is to use a block tester.
Silly question but one that is often overlooked... have you checked to make sure all your connections and cards are secured tightly?

Almost forgot - how are your fans connected? are they a direct connection to the board or are they Molex connctions? The LEDs are most likely powered straight from the board.

[crashisme]

Thanks for help Janine. I just triple checked all my card sand connections. Everything seems to be in good and tight. The emachines tech had asked me to pull out the RAM and power up but that did nothing. I even switched sockets for the RAM. The fan in the heatsink connected to the MoBo . I can't tell where the fan behind the power supply is plugged in because it's in the enlosed case. The leds are def. plugged into the MoBo. I did notice something strange when I was just checking my connections. The connection from the power supply to the MoBo is a 20 pin. The new Power Supply (upgrade) is a 24-pin that came with a short ponytail? to connect the two together. On this short cable, the metal inside one of the 20 holes is missing. This is the part that directly connects to the MoBo. On my old Power Supply, this is not the case. Does that make any sense?

[JANINE]

Yes it does. It seems like you might have the wrong power supply for your motherboard. Can you take a picture of both the connectors on the old PSU and the new one showing the PINS and pop them up here for me to view.
While you're about it trace the wire back from the case fan and tell me where it leads into.

[crashisme]

Figured it out! The last thing on my list was wondering if the processor was shot as well. After you told me to double-check all my connections, I did so but later realized I hadn't double checked how the processor was sitting on the board. I took it and put it back on again and whalla! Thanks for your help Janine, I appreciate and look forward to coming back once I run into my next problem!

Scott

[JANINE]

Hooray, another machine up n running. Cool stuff :D

[MaverickZ]

Make sure your mobo and cpu are compatible with each other ( make sure the sockets are the same )and your cpu is seated correctly in your mobo.