Newly built system starts but doesn't connect to monitor

[mrducga]

Hi everyone,

As title explained, my computer started, everything seemed to run fine but couldn't connect to a monitor.

These are the components, all brand new:

Motherboard: ASUS M4A77T (http://uk.asus.com/Motherboards/AMD_AM3/M4A77T/)
CPU: AMD Phenom II X6 1090T retail pack with heat sink (http://shop.amd.com/US/_layouts/shop/ProductDetails.aspx?productID=HDT90ZFBGRBOX&region=en-us)
RAM: CORSAIR 8GB XMS 1333MHZ CL9 (http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=390323487102)
Video Card: ASUS Radeon 6850HD (also tried a SAPPHIRE HD5450 but didn't work either)
Power Supply: G7 Power Extreme 680W (http://www.maplin.co.uk/680w-g7-power-extreme-atx-psu-345571)
Hard Drive: Samsung Spinpoint F3 1TB 7200rpm SATA (http://www.play.com/PC/PCs/4-/15250267/Samsung-Spinpoint-F3-HD103SJ-1TB-3-5-inch-Internal-SATA-Hard-Drive/Product.html?_%24ja=tsid:11518|cat:15250267|prd:15250267)
Monitor: Samsung SyncMaster P2450H (http://www.samsung.com/uk/consumer/pc-peripherals/monitors/design/LS24LRZKUV/EN/index.idx?pagetype=prd_detail)


Full Story:

I bought the parts separately and got them all yesterday. Read the mother board manual and followed it step by step and connected everything together. When I started the computer, there was no beep (system speaker connected) but the monitor couldn't recognise any input (tried both DVI and HDMI cables).

Initially I thought it was the problem with graphic card so I bought another one (SAPPHIRE HD5450) to try but no luck.

One thing I noticed was the 1 PIN from the 20 PIN power cable of my PSU is missing. Might this be the cause of the problem?

This is the picture I took of my CPU setup:

Many thanks.

David

 

[shortstuff_mt]

The checklist in my signature was made to troubleshoot this exact problem. I can tell clearly from your picture, though, that your 4-pin CPU power connector isn't plugged in. It's step #2 in the checklist.

 

[mrducga]

Thanks for your reply. However, the 4-PIN CPU power cable from my PSU is not long enough to reach the 4-PIN CPU power slot on the motherboard. As you can see my PSU is located at the bottom of the case when the 4-PIN CPU power slot on the motherboard is located near the top.

Shall I get another PSU with longer 4-PIN power cable?

 

[shortstuff_mt]

Do whatever you need to do, but the computer will not work without power to the CPU. The PSU is the most important piece of the computer. Don't get a cheap one or you will regret it. You need to make sure it's at least 80+ certified and has active PFC.

 

[mrducga]

Thanks for such a valuable advice. I really never thought PSU is that important. Will buy another PSU tomorrow and hopefully it will solve the issue .

 

[mrducga]

Just want to say thanks again for your very helpful advice, I bought a Corsair 850W PSU and now the system is working smoothly . Posting from my newly built PC now .

Another minor issue which is bugging me is that when monitor is connected to my graphic card using HDMI cable, the display does not fit the whole screen (2 black spaces on left and right) but it displays fine if connected via DVI cable. Any advice regarding this please?

Many thanks

 

[shortstuff_mt]

That's great that the new PSU solved your problems. Congratulations on getting a running homebuilt system!

It sounds like the display is defaulting to a different resolution when connected by HDMI. I would check the settings in the display drivers and make sure the resolution is set to the monitors native resolution.

 

[andrews013]

Did you install drivers for graphics card?

 

[mrducga]

Yes I did install the latest drivers for the graphic card. Will try shortstuff_mt's advice now . Thanks guys.