CPU cooler fan drawing too much power.

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Chris Law

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Feb 13, 2015
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Turns on. CPU Cooler fan sounds like a battery vacuum. Computer turns off, tries to boot again. Same story.

Turns off. Boots again. Boots as normal, but no display is seen. It gives me the usual BIOS error, something about system voltage being too low, but I always dismissed that as the computer booted to normal without any reboots straight after turn on.

Take out the video card, computer boots as normal.


I recently installed new RAM. It worked fine for a few days with the new RAM inside. Could that be the issue?

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My dell service tag: 96XTT1S

Specs:

Dell Core Duo E6550

Some sort of ATI Radeon card

6gb DDR2

unknown PSU supply or voltage

unknown CPU Cooler fan or voltage. I'm assuming the CPU cooler was just made by dell.
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Any and all help is appreciated!
 
Solution
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One thing that I forgot is that the 755 is from the era when bad capicitor were a common problem. Take a look at all the caps with labeling on the side and flat metal top caps with K,orX shaped groove cut into it. The top should be flat and shiny. If they're bulged up, or discolored in the grooves they're failing. They can also leak out the bottom. This could explain a lot of your problems.
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william p

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Sep 22, 2010
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I ran your service tag and got a dell Optiplex 755 result so I'm going to assume that's what you have. I don't know if it's a Mimi Tower MT,Desktop DT, Small Form Factor SFF or what.
Some of the old Dells ran the fan off of the CPU 12V. header. I've had them crash when overclocking due to the fan speeding up.
So here are my thoughts on this.
1.The fan draws 1.3Amps at full speed.
2. It a PWM fan and shoudn't run over 30-40% speed unless there is a cooling problem.
So first check your CPU cooling. Is there thermal paste between the CPU and heatsink? Is the heatsink cover sitting on some wires? Is the airflow blocked before or after the fan?
Next check the fan wiring. The blue wire controls fan speed. if it's broken or loose the fan will run 100% speed.
Last but not least the PSU may be dying ( but that doesn't explain the fast fan). It should be able to run that 65W CPU and the fan. Check to see if it's a Dell PSU. That computer needs 22A on the 5V. rail and some aftermarket PSUs don't have it. Taking the GPU out takes some load off of the PSU. I would swap it out with another Dell PSU and see what happens (aftermarket with 22A 5V will work if that's easier).
You may have a temp. problem, causing a fan problem, that's taking down the PSU. If none of that works I would suspect a dieing MB.
 
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Chris Law

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That is the correct computer. Small form factor if I remember correctly.

Dell PSU.


Output = +5V 18A MAX

then down the bottom it says +12V /17A. Within the output section. Can't they make these bloody things easy to read?

MB has never had an issue like this until now.

Can't see a blue cord anywhere near the CPU Cooler besides the blue cable running under my HDD that seems to connect to some sort of fan, sitting right under the HDD. Like, glued onto the HDD right under.


I'm not game enough to take up the fan and have a look. I only go that deep when I need to.

The CPU cooler does look different though. A quarter of the CPU is even exposed.


No wires seem to be interfering.


 
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Chris Law

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If it helps, on the 3rd startup. It boots fine. A little more noise than usual from the CPU cooler, but i'm assuming it proceeds as it gives me the usual two beeps. No video output though, that's the issue. Checked all my connections, VGA and all. Nothing.

If I remember correctly, I looked at CPUID and it said the new sticks of RAM had the same power requirements as the original sticks.
 
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william p

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Sep 22, 2010
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Please tell me what Dell you have and the size case. An old Dell Mini Tower should have a 305W PSU with 22A on the 5V. If it's a smaller version then what you have may be correct.
The fan should have 4 wires coming from it. Dell usually twists them up red, black, white and blue. There should be a 5 pin plug going to the MB to the right of the cooler housing facing the computer from the front.
I don't think 2 beep sare normal. Are there any lights on in the front other than the green power on light. Dell has 4 diagnostic lights there. My old Dell doesn't beep at startup.
You can see part of the CPU socket cover on these but not the CPU itself. The CPU is turned 45* and the corner of the socket sticks out.
 
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Chris Law

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Feb 13, 2015
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If i'm correct, it should be a dell optiplex 755 small form factor. Look for the one with two usb ports on the front. Head and mic jack, optical drive and floppy drive slot.


I will take a video of the unit powering up and show you at a later time, as work is calling my name... Hooray!

Here is all my Supply Unit info:

dKpjvf3.jpg

 
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Chris Law

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Feb 13, 2015
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My post didn't seem to go through, but I eventually fixed it. I found the CPU fan cord and it was a bit loose. One of the surrounding diodes was also a bit limp, but that just had to be corrected. It works fine now.

If anyone has any solutions if the computer decides to require twenty boots before actually being able to reach the Splash Screen, do post.
 
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william p

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Sep 22, 2010
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One thing that I forgot is that the 755 is from the era when bad capicitor were a common problem. Take a look at all the caps with labeling on the side and flat metal top caps with K,orX shaped groove cut into it. The top should be flat and shiny. If they're bulged up, or discolored in the grooves they're failing. They can also leak out the bottom. This could explain a lot of your problems.
 
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