2 CPU fans died in a few days, what's going on?

Could it just be your bad luck that the replacement CPU fan died too? :emotion-6:  Will the eBay seller give you your money back?

Reboot and press F12 before Windows starts to load. Go to Utilities partition and run the fan tests. That tests the CPU fan.

Is the power button blinking or solid amber? Read this about the power light on the 8400

 If the CPU fan fails, usually you get a "fan failure" message when you reboot, and if/when the system overheats, it shuts off to protect the CPU. So are you sure the problem isn't with the power supply fan?

Ron

As I noted, the fan supplier is sending me another identical fan at no cost to me, not even shipping.  So, no refund, but another new fan.

The power button is solid amber.

I wasn't home the first time that it happened, but the second time I was sitting right in front of the computer and no message about "fan failure" or anything ever popped up.  The fan started making a weird sound, then the mouse froze, and the system was locked up.  I was unable to ctrl-alt-del or even shut down by holding in the power button.  I had to turn off the power strip, and when I turned it back on that's when I got the solid amber light.

When I replaced the fan, the system came on and booted up like nothing had ever happened.

So, in terms of a possible short, could it be on the mother board?

If it is, is it something that could be repairable or am I probably out of luck and need a new system?

 darclyte

A Solid Amber power switch LED could indicate a failed motherboard.

Try the case fan replacement and if this fails, then you could be looking at replacing the motherboard.

While the case is open, check the motherboard for any capacitors with bulging tops or are leaking, the tops should be perfectly flat.

Also, check the sequence of the diagnostic lights on the back panel of the case, see HERE

If the motherboard has failed, you would need to buy replacement, most of the replacement Dimension 8400 motherboards available, will be 'Refurbished' aka Used.

Bev.

Hi Bev,

Thanks for the info.

When I power it up, I get the amber glow of doom on the power button, but none of the 4 lights on the back light up.  According to Dell docs, that is a pre-BIOS failure.  That makes sense because since the CPU fan isn't working, it won't allow the system to try to boot up.

I looked at the mother board and all looks normal.  Nothing bulging or leaking.

Once I put in the new replacement fan, I'll power it up and check the back lights and see if there is a "code" or not.

Thus far, it just seems that it's the CPU fan that fails, but after 2 essentially within 2 operational days of each other, I am concerned as to what the cause would be.

I'll post back once I replace the 2nd fan with the 3rd fan.

Thanks again!

~ÐL

Bad power supply has fried things.

New fan isnt likely to change that.

Does it have to be the same make and model power supply, and a Dell, or can I get any power supply I want?

It's a 350W power supply, could I get a 500W unit instead?

Thanks all, I really appreciate the helpful advice!

darclyte

You don't have to install a Dell PSU and upgrading to 500w power supply would be fine.

The 8400 PC's, use a standard ATX PSU with a 24pin or 20+4 main motherboard power connector and no on/off switch, if you use a PSU with a switch, then you will have to modify the back panel for it, by cutting a hole for the switch. 

 The power supply needs a minimum of 2 SATA power connectors.

Bev.

Thanks Bev, I'll look into a different power supply, but I did find the exact same model online.

Thanks again for all the help, and I'll update going forward.

darclyte

You can find Dell 8400 compatible power supplies, w/o the on/off switch HERE

Bev.

Awsome!

Thank you!

Awsome! Thank you!

darclyte

You are welcome and good luck.

Bev.

I bought a heat sink, so I suppose that I should replace it as well.

I'm just concerned about doing that as there is the whole "paste" that has to be applied and how to do it correctly...seems like a real pain.

Maybe what I'll do is once I get the power supply, I could take the new fan, the heat sink and the power supply to a computer repair place and ask them to install all the parts for me as they would know what they're doing more than I would.

 darclyte

It's fairly easy to apply the thermal compound.

Directions for cleaning and applying thermal compound, are HERE.

You only need a small tube of thermal compound, this can be purchased from any computer store.

Bev.

Ps. You did buy another Dell Dimension 8400 heatsink, as both the heatsink and motherboard retention bracket, are Dell proprietary items.

Yes, the heat sink and CPU fan that I bought are the exact same as those that came with the system.

I also found the exact same power source, but I haven't bought it yet as, luck would have it, I needed to come up with $600 for a car repair.

Oy.

It never ends.

So, it'll probably be a bit before I'm able to get the part and figure out what to do with them.  I think I'll ask my friends over and have them help me, and I'll feed them in exchange.

My brother has the thermal compound so I'll get it from him, take a look at the link, and have my friends help me out since they're really good at this stuff.

I actually helped build a computer from the case up with my ex wife a few years ago, so I'm not all that concerned...I just want to get it done right and not have to worry about it anymore.

On another note, my friend in the military just got a new Dell Laptop, and sent me her old Inspiron 6000.

Unfortunately, she had AOL on it and when she uninstalled it something went awry.

So, I'm going to reinstall Windows XP and just put in my work software and it'll just be used when I'm away from the house but have work to do.  I'm gonna save up and get the maximum sized HD for it (which I think is like 150GB or so) and buy Windows 7 to put on the new HD, and THEN I'll make it the laptop that I REALLY want.  At least my friend maxed out the RAM already.

Thanks again for your help, and the above link!