Replacement components for a computer that does not post

[Neville310]

My desktop computer has been exhibiting unusual behavior over the pass week. Unfortunately, my pc does not always post when the power button is pressed. Sometimes, the computer turns on after several hours. When the computer does not post, I cannot hear the drives spin up or any posting process (including beeps).

My initial thoughts relates to the motherboard or video card since the power supply is less than 6 months old (Corsair TX750W). When the computer turns on, it does not encounter any errors or hiccups; and performs as expected.

Unfortunately, my time is limited for researching and troubleshooting the situation since this computer is down. I have re-seated all the components inside the case, yet do not have additional components to swap in and out. My first inclination is to begin looking into replacement components, yet I was not planning a major system upgrade. So I humbly request suggestions on replacing my motherboard, processor, and video card. My current system has processing power for most computing tasks except when doing heavy multi-tasking with streaming HD video. My requirements for replacement components would revolve on a dual monitor setup; moving large files, file archiving, and HD video decoding in a multi-task environment. This rig does not serve as a gaming machine. Value is a top priority for replacement components. My budget will be between $300 and $400.

AMD seems like the better value. The Phenom II X6 1090T looks good with 6 cores. The motherboard and video card are not easy choices. It has been 5 years since my last system build and the technology has rapidly evolved. The motherboard should have at least 6 Sata connection (most seem to have 4) and on-board sound. USB 3 would be nice, yet not essential. The video card should be powerful enough for basic photo editing and viewing HD content. I do have 4GB of OCZ PC2 6400 ram from a previous hot deal, yet did not work under my current setup. Below is a short list of potential candidates for replacement component and my current system.

I am hoping this thread would begin a discussion on the components that offer the best bang for the buck. Any suggestions would help me avoid major disappointments with getting this systems back online.

Replacement Components
-----------------------------------
Phenom II X6 1090T Black Edition
ASUS M4A78
XFX Radeon HD 4670 Video Card or something under $150

Current System
---------------------
Processor: Athlon 64 X2 4400+ (2.2GHz) 1MB L2 Cache Socket 939
Heatsink: AMD Heatsink-Fan: Thermalright XP-90C w/92mm Fan
Motherboard: A8N-SLI Deluxe
Video Card: XFX GeForce 7800 GT 256-MB PCI Express
Power Supply: Corsair TX-750w
Memory 2x1GB 400Mhz PC3200 DDR RAM 184PIN DIN
Monitor Dual Dell 22 Inch 2209WA

 

[trents]

If it works flawlessly when it does turn on I would feel safe in ruling out the CPU as the problem. Have you tried taking all but one memory stick out and trying each stick in each slot one at a time? How about removing the video card and using the onboard video? Or, do you just have the upgrade fever?

As far as your budget of $300-$400 bucks, you might be able to do it except for the video card. You'll need a new motherboard ($100+), A new CPU ($200), and unless you've going with an AM2+ board (and I would not recommend that), new ram ($55) as you can't use your DDR2 ran in an AM3 mobo.

 

[Randyman...]

I'm assuming you've checked the obvious stuff like a faulty front-panel power switch (just had a similar issue and this was the culprit), an intermittent shorting wire (even BEHIND the MoBo), proper MoBo standoffs, loose/corroded/dirty ATX connectors, etc? Any wiring pulled extremely tight?

Be careful - but have you tried to run the system case-less?

 

[trents]

I'm assuming you've checked the obvious stuff like a faulty front-panel power switch . . . Be careful - but have you tried to run the system case-less?

Excellent suggestions. Trace the wires from the front panel power switch to the motherboard front panel pin block. Pull the power switch connector off the pins. Then take a screw driver tip and short across the pins, don't hold it there long, just a spit second.

 

[Neville310]

My computer has not started in a week. I am discouraged that it won't come back to life. Changing the motherboard battery made no difference. Today, I pulled out the memory, modem, and disconnected the drives. The paperclip switch technique did not make the computer post. The computer switch seems to work on the case. After opening the case and pressing the power button, the motherboard LED light, CPU fan, and graphic card fans turn on. The power supply could be an issue, yet it is fairly new and a highly rated brand (I still have the box). I don't know about troubleshooting the power supply otherwise. Generally, the computer becomes unstable when other components act up.

I have never had a computer not post for me (even with a bad power supply).

 

[trents]

If fans and lights turn on then its beginning to look like the mobo rather than the PSU. Do you have another PSU you could swap in the case to check that for sure or do you have access to another computer you could put your current PSU in to check it under load?

 

[Tech Tweaker]

I'd check your motherboard for blown capacitors if you have not already done so.

They are the things that look like little cans that are scattered all over the board, if you don't know what they look like. If you have a lot of them which have rounded/expanded tops (they are normally flat if they are in good working order) that may be a contributing factor to the issue. I only suggest this because I have encountered similar issues in the past where I worked on computers that would not post sometimes or at all, and they had one or two or multiple blown capacitors on the board.

 

[trents]

Bad capacitors don't always show the classic evidence of rounded tops or leaking oil.

 

[theELVISCERATOR]

a multimeter is handy in these instances, I highly doubt your corsair PSU is the problem almost impossile, but always good to actually check the rails both OFF and on the mobo.

I always suspect mobo first these days.

 

[bda1967]

I always suspect mobo first these days.

I find that true on proprietary machines like DELL, HP and Gateway and in that order.

 

[Neville310]

@Tech Tweaker

Unbelievable! The motherboard has one bad capacitor. I found a rounded capacitor at CE3