Alert! Previous Fan Failure.

Well the CPU Fan blows onto the CPU Heatsink. Just in case

There just was no exhaust...It was flopping around when I opened it, fell out into my hand...One thing I like about Dell is the color coding and ease of parts removal/installation...virtually no tools required. Of course, this also means that if you bump you 'puter table too hard, you may knock the little feet that hold the fan out of their little holes....

Oh, and it is so straight forward, there is no way to reinstall it incorrectly...

I really prefer screws over "pop-in" parts... Hard drive screwless rails are neat though

"Alert" problem has grown!

Everyone, thanks for your helpful insights.

Unfortunately I seemed to have moved onto stage two of the problem

I get the "Alert! PFF" message and then Push F1, etc. But now my keyboard will not respond, although it works when I'm in the BIOS. So now it just hangs on this message and I can't boot into the OS. I've tried several keyboards with the same result.

Any words of wisdom will be greatly appreciated!

cheers,

Bruce

Sounds like Bruce has plugged a fan into the wrong motherboard header

Black Cats post worked for me for this error....Thank you sir

Noisy Fan

Good Morning, I have a Dell 4600 Series Desktop, the fan on the tower is very noisy, does anyone have any suggestions. I did get the Fan Failure message and pressed F1 and things went okay. But the fan is so very noisy, any help or tips would be greatly appreciated. Thank You.

"Alert! Previous Fan Failure" Diagnosis & Repair Checklist

TECHSPOT forums have helped me with great tech advice in the past, so I am offering the following diagnostic procedure as my first post in these forums. It includes almost all of the recommendations made throughout this thread combined with some from my own experience with this problem as a technician. I did my best to give credit to those who posted great recommendations.

"Alert! Previous Fan Failure"
Diagnosis & Repair Checklist:

STEP 1: CHECK THE FAN. If the fan is dead, wobbling, smoking, or on fire, it must be replaced. Use compressed air to blow any dust out of the fan. LOOK CLOSELY and make sure the fan is connected to the appropriate power connector on the mainboard; often there are multiple power connectors for the CPU fan and CASE or SYS fans. Check that the entire assembly (fan, screws, heat sink, clips) is properly mounted in the retention bracket; the metal heat sink should be held firmly against the CPU with snugly fastened clips. If the assembly seems loose, it is either assembled improperly or it is broken. If you find any of the above to be true, skip to STEP 5.

STEP 2: ENTER THE CMOS/BIOS SETUP UTILITY. Getting there isn't always easy. Since the "Alert! Previous Fan Failure" problem is primarily specific to Dell computers, tapping on the F2 key after turning the computer on should get you into the BIOS/CMOS setup utility. If it doesn't, try the DEL key or some other F# keys, just be careful to not restore your computer. If the computer does not seem to be receiving your key strokes, make sure your keyboard is in good working order and properly connected to the computer (and not plugged into the green PS/2 mouse jack). If the setup utility asks for a password, enter it. If you do not know what the password is, look on the mainboard for a jumper that will reset the CMOS password; if you can't find a password reset jumper, GOOD LUCK. You could search the internet for CMOS/BIOS password removal tools and perhaps get lucky and feel like a hacker!

STEP 3: CHANGE THE CMOS/BIOS SETTINGS. Once you have successfully entered the CMOS/BIOS setup utility, you are in the home stretch. Clearing the event log seems to have been the #1 SOLUTION for a lot of people who posted here, which makes sense because the error message says "previous fan failure" and not "current fan failure". Changing the "DO NOT report keyboard errors" setting was the #2 SOLUTION which really does not make sense because the keyboard and fan operate at different voltages and are generally unrelated, HOWEVER! since it worked for them it might work for you. You can always try resetting the CMOS/BIOS settings to the "default" or "safe" settings, but you may notice your computer behaving differently afterwards, and it is therefore not recommended. It seems that all CMOS/BIOS setup utilities are a little awkward to navigate, so look for instructions on the bottom or right side of the screen if you are having trouble.

STEP 4: UPDATE THE BIOS. Hopefully the error message is gone. If not, there are a few more things to try. The reason why this procedure has a reputation is because every once in a while it quickly and unsuspectingly destroys people's computers! (actually, just their motherboards!). During the BIOS update process, if the procedure fails for any reason, the computer will no longer boot and the motherboard will be have to be replaced. With that in mind, go to Dell's support web site, enter the computer's model number or service tag, and download the most recent BIOS update (located in the device drivers section). Follow the instructions carefully and guard the power strip.

STEP 5: REPLACE THE FAN. If the error continues to appear, there may be a problem with the fan, its wires, or the connector. If you replace the fan, make sure it is the correct size (92mm fan is common with Dells as mentioned earlier by "benthere") with a power rating of 12 volts and around 0.42 amps (as mentioned earlier by "wsnett") which should draw about 5 watts. If you must remove the entire fan & heat sink assembly, be sure to clean up the old thermal compound residue using isopropyl alcohol and then apply new thermal compound; make sure the heat sink is seated and secured firmly against the CPU; make sure the clips are properly attached to the brackets; make sure the fan is plugged into the motherboard properly.

STEP 6: STILL HAVE THE ERROR? "snoopindaweb" posted this key sequence at power-up: turn on -> CAPS LOCK -> NUM LOCK -> SCROLL LOCK -> ALT+E -> ALT+B -> ALT+F, then do an "Automatic IDE Configuration". I haven't tried it because I didn't need to, as the list of recommendations above solved the problem.

STEP 7: BUILD A NEW COMPUTER. If you are frustrated and don't like the way Dell builds computers, and you feel the need to post unhelpful, angry comments in an online forum like TECHSPOT, then you must step away from the keyboard, gain control of yourself, take responsibility for your anger, and claim ownership of your computer by building one yourself. Its fun, educational, and impresses the opposite sex.

I enjoyed putting this together.
I really hope it helps someone.

the error can be BYPASSED fairly easily, some of you will kick yourselves, but here goes:

now this is will defeat the failure, if/when your fan fails and overheats the CPU; the computer WILL shut down(more likely just shut off) automatically, regardless of this hack. so not to worry too much.

say you replace the fan with another type. (ie. not the original) , the fan works, but it will still give the error.. why? resistance. the original fan i had was 1.2 amp 12v blower fan. Yes, i said 1.2 amps SOME of them have 0.42 amps (how the motherboard supported this i do not know, i will see if i can get a model number of that fan) this is a 4600C Dell, which I love BTW except that i cant get any fan speeds or anything under lm_sensors for some reason, looking for help on this myself)

To replace it with a completely different fan and NOT use the fan header (using the 4-pin molex connector)

if your fan is rated at 1.2 amps you need a 10 OHM / 15 watt resister across the red/black wire; with the white wire (signal) going to the negative of the header. @ .42 amps you will need a 5 watt 28 OHM resister.

OR better yet:

use the fan header: red(pos) / black(neg) to connect your fan and simply connect white(signal) wire to negative

like i said it is a BYPASS, it will work.

finis

had same issue, supyrow instructions are spot on.

I wouldn't be doing this :suspiciou

Just buy the correct fan.
And by the way, this is one of the causes of many No POST issues on system builds. Where the User has put in the incorrectly rated fan

Comments on Custom Fan Modification

The 1.2 amp 12 volt blower fan that you mentioned is typical in Dell computers that have passive cooling (no fan on the heat sink) complimented by a green shroud to help control air flow. The fan requires higher power consumption to increase the CFM (cubic feet per minute) because its proximity to the heat sink is more distant. This configuration is not common and therefore most replacement fans will not work properly. Moreover, controlling the speed of this type of fan will require a variable pulse width modulator instead of a rheostat, which is ultimately not worth the complication (unless you are repairing a computer on the international space station and do not have a decent part supplier ... then again, I doubt that the ISS has any Dells, and therefore I digress...)

Otherwise it may be a CPU fan for something like an Intel Xeon processor or a case fan for a power hungry server.

Regardless of what is "proper" and the fact that you can "buy the correct part" ... I find your solution to be interesting, experimental, and ultimately impressive. Sometimes there are no spare parts available and it takes a custom modification to get the job done. Your math is not exact, but it is close enough to not fry the board, and therefore ... if it works then it is a solution!

I just replaced a CPU fan/heatsink on a 2002 Intel Dell desktop. I used another heatsink assembly taken from a scrap motherboard. The 2 assemblies were similar, but the mounting brackets, attached to the motherboard were different. I was able to remove the burned out fan assembly completely, and the new heatsink assembly fit fine. The "Alert! Previous Fan Failure" stopped

MarkMartin57, thanks for your response, i appreciate it!

what is wrong with the math??? good luck trying to find a 14.4 watt resister lol
the 28 ohm 5 watt; however, you would have to go with 30 ohms. i couldnt find one of those either.

-----------------------------------
I would also like to note.. I dont know what FanSpeed or other similar software for windows would say about speeds or anything after this bypass on any other board, this was a fix for the dell 4600C which i have, and ive never had any sensor software give me ANYTHING for the board I have. Since i'm running linux, for some reason even lm_sensors will give me nothing even though it found the chips to read temps and speeds. Before and After the bypass.

that is all.

Good Luck

Same Problem

Hi,

I have had the Dell Dimension 4300 for 8 years with hardly any problems.

Recently the above has started to happen.

As I needed a PC urgently I bought a new PC.

I have managed to get the data from the hard drive using a Hard drive enclosure, and transferring data to new PC.

I now want to repair the old machine to use it as a spare secondary machine.

I am happy to experiment as I consider it a write-off (ish).

1) The fan(s) are working as I can see them turning.
2) I have tried clearing all the logs etc - doesnt work.
What happens is as its loading a blue screen of death appears and then it just starts re-loading atnd the same thing happens.

How can I find out if the CPU has fried?

I am happy to replace it, if I could confirm thats the problem.

I could but a 2.8 ghz chip for £80, 1 Gig of RAM for £80 and a hard drive, and all of a sudden I have a half decent machine.

Its only worth it if I know the CPU has the problem.

The other problem I have is that i stupidly deleted all the data from the hard drive I took out after transferring the files I needed.

Your help would be greatly appreciated.

PS: I am not the greatest with PC's.....

Fan failure

If anybody was able to help me - it would be really appreciated.

8 years is way past the computers useful life...there could be multiple hardware failures

This could have benefited by being in a new thread... If the CPU is an Intel socket 478, there are still motherboards available, with updated memory, and on-board video. The motherboard, power supply, hard drive, any memory and CD drives are most likely trash