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PC power issue, motherboard may be dead? Not sure

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July 24, 2012 8:09:43 PM

Hello, I'm visiting my grandparents out of town and they had a computer issue they wanted me to look at, cause I'm the family geek. Their desktop wouldn't even show signs of turning on, so I went out and got them a new power supply. Upon inserting that and plugging all the same connections in, it powers on the PSU fan, HDD, dvd drive but nothing else. I then thought it could just be a fried mobo, but the LEDs on the front of the case that only connects to the motherboard come on. I'm kind of clueless right now. The CPU fan nor rear case fan turn on, both of which are plugged in. It wouldn't surprise me if it was the motherboard considering how old the PC is, but I sure as hell hope it isn't.

Here are some pictures of it, I would love some suggestions. Thanks

http://imgur.com/a/15CgE#6sVZq
a c 133 ) Power supply
a c 157 V Motherboard
July 24, 2012 8:28:03 PM

Welcome to Tom's Hardware Forums,
Although some of your pictures are very nice, I would really love to see those cables bundled up behind the PSU. I would be able to get a better idea of all I am looking at - I seem to lose cables as they are intertwined among themselves. Or at least pulled out of the way of the mobo and needed cables. Just a suggestion...
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July 24, 2012 8:31:19 PM

Thanks for your reply, I know for a fact that all the cables are plugged in where they should be. I examined what the previous PSU had plugged in and copied it. Although it's not what I'd like to hear, I think it's the motherboard that's the issue. Hypothetically speaking that the cables were all plugged in right, would you agree?
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a c 133 ) Power supply
a c 157 V Motherboard
July 25, 2012 12:05:04 AM

Okay, we'll assume the cables are hooked up right (what I can see appears to be - cleaned up cables would make it easier to ensure). If that is the case, then you want to see if the are any lights lit on the mobo itself when powered on.
Also, before declaring the mobo dead, check out this thread - see if any of this helps
http://www.techsupportforum.com/forums/f15/solved-mothe...
I believe that is the mobo... if that doesn't help, I think you can safely pronounce it "dead"
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July 25, 2012 7:02:47 AM

1. Judging from your pictures, mobo's battery has been removed. Are you sure you have put it back?

2. There is a buzzer on your mobo. Have you heard beeps when you turn on the power?

3. Removing your RAM and unplugging the power connector of HDD,CD-ROM, only connect your mobo and CPU with PSU. If your main components is OK, you will hear beeps after you turn on the power.

4. If No beeps after putting back the battery and removing the RAM, try to check your CPU through the following way.

Removing your CPU fan, then power on and power off after 1~2 seconds. Touching the CPU surface. If your CPU is ok, it will become hot.
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a c 133 ) Power supply
a c 157 V Motherboard
July 25, 2012 7:13:29 AM

kissingman said:


4. If No beeps after putting back the battery and removing the RAM, try to check your CPU through the following way.

Removing your CPU fan, then power on and power off after 1~2 seconds. Touching the CPU surface. If your CPU is ok, it will become hot.

I would recommend against that technique as it does not ensure the CPU is "ok" (only that current is going through it) nor can it tell you if the mobo is bad - only whether current is going to the CPU or not.
If you do choose to try that remember to clean off all thermal compound from HSF and CPU and apply new compound.
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July 25, 2012 8:22:01 AM

C12Friedman said:
I would recommend against that technique as it does not ensure the CPU is "ok" (only that current is going through it) nor can it tell you if the mobo is bad - only whether current is going to the CPU or not.
If you do choose to try that remember to clean off all thermal compound from HSF and CPU and apply new compound.


CPU is a Sequential Logic Circuit. It running based on Pulse signal. PSU just provide Direct-current(DC) as the power of system components, but it doesn't enough! If we wanna make it run, Pulse signal generate by Clock Generator is required.

We can prove this by a fact: More higher of CPU frequency, more heat it will produce.

So, as my opinion,only the current going through the chip won't make it become hot, and i always do it like this in reality.

Of course, just show me the mistakes if i was wrong. :) 
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a c 133 ) Power supply
a c 157 V Motherboard
July 25, 2012 8:33:40 AM

Why remove HSF? If heat is generated, it can be felt on the HSF - running a CPU without a HSF is just not a wise choice if there is any way to avoid it (IMO). I'm pretty sure I have never seen it recommended anywhere else.
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July 25, 2012 9:32:51 AM

C12Friedman said:
Why remove HSF? If heat is generated, it can be felt on the HSF - running a CPU without a HSF is just not a wise choice if there is any way to avoid it (IMO). I'm pretty sure I have never seen it recommended anywhere else.


Of cause you can judge whether CPU is ok by the temperature of HSF, but the question is you need to wait 5~6 minutes after the temperature raised up, and you still need to avoid the interference which from ambient temperatures & human body temperatures. besides, CPU has perfect overheat protection function, and there is no need to worry for it ( My old Pentium4 2.4GHz was overheat about 2 months ago because the fan has been seized up. The system shut down automatically. I just let it cool down and it was recovery by itself). So, if we can get the precise result in few seconds, i don't see any reason why not.

BTW, If having trouble with removing HSF, just ignore what i just mentioned.

P.S. : I still remember a story happened about7 years ago. My friend forget to plug back the power cable of CPU fan after clearing the machine. The system shut down automatically but fail to running again even after the temperature has cool down. There was a MSI NF2 mobo with AMD Barton 2500+. I though the CPU was burn out first of all, because CPU won't become hot even after removing the HSF. But the truth is mobo has transition to a "protection" mode, if you wanna make it running again, clearing BIOS is required.

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a c 133 ) Power supply
a c 157 V Motherboard
July 25, 2012 10:26:14 AM

Let's just leave it and get back to the OP's issues - perhaps it will make for a very intriguing thread on it's own merit...
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