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Here is one for the group. I just replaced my loud whiny 60mm 5400rpm cpu fan and heatsink with a cool quiet 80mm 2800rpm cpu fan and heatsink (athlon t-bird 1.0g cpu). Suddenly the machine turns itself off after 4 seconds. Every time.
So I reseat the memory, video card, check everything, reset bios, no luck. Then I wonder if this retarded ECS K7VTA3 motherboard has a built in fail-safe for cpu fan speed. So I unscrew the new fan and put the computer on its side and lay the old fan on top of the new sink (the screwholes don't line up) and suddenly I'm back up and running. Then I check the bios and indeed it looks like there is a page of system vitals that the bios keeps track of, but only the cpu temp is an adjustable field. The fan field is not adjustable, in fact it only reports the speed (currently 5400rpm) and doesn't say what is the minimum before shut off. Cpu temp used to be 41C at idle, now its 34C (using the combo new sink and old fan). There is no way the new fan is causing overheating in 4 seconds so since it runs fine with the 60mm fan but shuts off with the 80mm, I am assuming that the 80mm speed is causing shut off. Somehow I've got to convince the mobo that the new fan is okay at a lower speed because its BIGGER you moron. I am a little peeved at this mobo right now, but I'll get over it. Especially if someone has an idea for me. Sorry for the rambling post.
I also tried one of the other motherboard fan plugs and that did drive the 80mm fan fine however unless the 60mm was also plugged into the main cpu fan plug, evidencing rpm's for babysitter bios, the system shuts down immediately.
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G'day,
Do you know what criteria the motherboard uses to detect a fault. You mention RPM but is that what it measures?? Or is it voltage and / or current? Just a thought, but you might be able to cut the monitor wire and feed it the signal it is looking for.
regards,
Elric
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G'day,
Just another thought: if you have two sockets for the fans, why don't you leave the other one in and use it to cool something else. Or, does it still make too much noise even when not mounted on anything?? Have you tried any noise reduction kits? I've seen these rubber mounts and springs that you can get to dampen the noise by isolating the fan from the mounting. You can also get cables with (I assume) resistors in them to reduce the voltage across the motor, which appears to make it run quieter. Mind you, I don't hnow how badly that will affect the CFM flow of air and hence the temp of your CPU.
Just a few thoughts anyway.
regards,
Elric
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My thoughts too Elric. What I did was plugged in both and it turns out that the 60mm fan does not even need to be spinning, just using up power. It was so loud though that I jammed the blades so that they would not turn and have hung it out the side of the computer. Its pretty hot and may blow at any time, but I've got my eye on it. My next thought is plug something else into this plug that is not in danger of frying out, but I don't know what to plug in.
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G'day,
Yes, they do tend to get hot if you jam something in the blades. I think what you should do id see if you can read (before it all burns off...) the current rating for the fan. Assuming it is running at 12V then you can calculate the equivalent resistance ie 12V @ 100mA (say) gives 120 ohms. Next calculate the power ie I^2*R=1.2 Watts, then derate for longer life (say double it ) and you get a 5W 120R resistor. Just plug that where the fan used to be and you will be ok.
That's the idea anyway, you will have to do the arithmetic for your fan. You can hang the resistor outside the case (just remember not to touch it!)without any problems.
The fan will probably have 3 wires (red/yellow/black); I think the red is +V (12), black is 0V and the yellow is the feedback wire. I can only assume that this is connected to the red wire internally, but I don't know for sure. You may have to connect these to together to get it to work.
Let us know how you get on.
regards,
Elric
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G'day,
Oops!! You spotted my deliberate mistake ..
1.2W derated by 200% is approx 2.5W..
You get the idea anyway.
regards,
Elric
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You've got me on the right track I think. The old fan is rated at .36A and the new one at .21A (max). So that says 33 ohms for the old one and 57 ohms for the new one, so I need a 33 or so ohm resistor at 8W or 10W. Hopefully I can get one in town somewhere.
However aren't the ratings for a max situation? I found a couple 60mm fans online that appeared to run at about 0.15A-0.2A, and it could be that my 60mm only runs at that amperage too. I have no test or probe equipment to do an actual measurement. I realize its probably not a big deal, but why waste a few watts when I'm not sure how close my old psu is to the edge already.
old fan
http://www.coolermaster.com/products/cpucooler/fcpga/dp5-6i31c.html
new fan
http://fanwholesale.safeshopper.com/2/37.htm?332Since the 60mm fan is right now at zero rpms, for now I plan to leave the wire for rpm feedback off the new resistor.
A funny part of all this is that while the new fan is slightly quieter, it turns out that my hd is the one producing the annoying whine that motivated me to replace the hsf in the first place.
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Elric - Actually I guess I'll need a 100 ohm and 50 ohm resistor in parallel to produce the 33 ohms. Its been 20 years since I did this sort of thing so anyone who reads this who wants to chime in is welcome.
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Better yet, a single 50 ohm resistor stuck into the 80mm fan's power leads will double its power consumption, and I can just plug that into the normal fan plug and then the mobo will think its two 80mm fans or one 60mm fan.
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G'day,
Yes, I calculated for maximum because I didn't know at what point the motherboard cut in. If you can run it at a lower current then by all means do so. However, a 10 W resistor will keep it much cooler, whatever value you choose.33 ohm is a preferred value so it should be available at your local electronics store ( Radio Shack, Tandy ).If not 100 and 50 will be fine.
I'm not sure why you want to put a resistor with your 80mm fan. This is what will happen: if you put it in series with the fan you will halve the power and reduce the speed by half (12^2/(50+50) instead of 12^2/50); to double the power you will have to put the 50ohm in parallel with the motor.
So, bear that in mind when you do the mods.
You can also go back to your 60mm fan a put a potentiometer in series and reduce the speed to see if it makes it any quieter. This will affect the cooling though.
Good luck,
Elric
ps it's 25 yrs since I first did this ..
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Following Elric's lead I have laid a 10W 50 ohm resistor across the 12V and ground leads of the 80mm fan and plugged it into the cpu fan plug with the 60mm out of the picture. This has doubled the current draw from this plug and apparently fakes the motherboard into thinking that all is well, so I'm good to go. Thanks to Elric.
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G'day,
Well, I'm glad that worked. I realise what you were trying to do now.
At this point it would probably be a good idea to think about failure modes ie will the motherboard still protect your CPU in the event of a fan failure. If the fan goes open circuit, we know that the 50 ohm resistor will look just like the 80mm fan on its own and the motherboard will shut down. If the motor goes short circuit then the 50 ohm resitor will be bypassed and it won't matter whether it is there or not.
I'm not aware of any other failure modes, so if anyone out there knows of any other condition that should considered please let us know.If the connector is on the motherboard, does that mean that the fan voltage is being varied, or is it still fixed??
regards,
Elric
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A funny P.S. to this story.
I was soldering the 50ohm resistor to the fan wire and accidentally shorted the 12v lead to ground, and also had absentmindedly not unplugged the cpu fan plug from the mobo. The system was off, but not unplugged. Dumb, I know. So I heard the dreaded POP of something being blown. The computer was then able to turn on but the 12v power to the motherboard was gone so the cpu fan would not start. Interestingly the system did not shut itself down since it was no longer able to monitor the cpu fan plug. So I took an old case fan and screwed it onto the heatsink and plugged it into a 4-pin psu plug and I am back up and running, since apparently I have no need for 12v power on the mobo other than the two 3-pin fan plugs, which are both now dead.
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Hello Johnho,
Recently I posted a message "How to enable AGP?", and I guess it was you (judging on the nickname) who provided the most useful reply. Just wanted to thank you very much. After reading the passage on the VIA drivers, I checked on the ABIT website, and found out that I only needed to update my VIA chipset drivers. So I did, and voila, my videocard now works in AGP 4X! With only 3833 3D Marks in PCI mode, after update I got almost 4700 3D Marks.
Thanks a lot again!Cheers,
rturro
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G'day,
And we were doing so well..... yes, soldering iron tips are earthed.
Did you blow the fans as well?? Do you know where the 12V runs to on the motherboard? Is it straight to the PSU connector? I really don't understand why these things are not fused. One fuse on that 12V line would have saved a lot of heartache.
Never mind, the pop could have been a shorted capacitor. I don't know the wiring of these newer boards, but the PSU still works, so you could wire up your 80mm fan to the 12V line at the 4 pin socket.
I don't know if a new PSU will solve the problem- there might be some electronics (ie a regulator)in the way.You could try tracing the tracks back and look for burn marks.
Good luck,
Elric
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