CPU Fan not detected

On many Dell's, unless you use a Dell replacement fan that will happen. 

Hi Fireberd,

 

Thanks for the prompt reply. Sorry I ommited to say in my original post that both parts I replaced were genuine Dell replacements.

 

Dave

Dave, just for the heck of it try going into the BIOS Setup and clearing the Event log.  The boot up message maybe just a reminder of a past event.  You can click here  Broken link has been removed from this post by Dell> for your model's on-line user Guide and the section pertaining to the BIOS Event Log for your reference.

Hi Majestic,

 

Thanks for the idea, I'm afraid it didn't work. :smileysad:

 

Dave

Dave, the only other thing I can think of is double check the plug.  If it had a three prong socket make sure the plug is on all three pins and facing the right way. 

Does it show anything in Device manager, or does the error only show up during the boot process?

CPU fan is not a 'managed' device; Windows has no awareness of it.

 

The fan generates a tach signal to show that it's turning.  The absence of that signal is what prompts the error message.  The new fan may be defective, not generating tach.  The wires or plug may be defective, not transmitting the signal to the MB.  Or the MB may be defective, not recognizing the signal--but that's less likely since you didn't have the problem before.  Or did you?  Was the error message the reason you replaced the original fan, and was the original fan actually spinning or not?

 

As I recall, the tach wire is white.  On 3-wire fans, it's the wire that's not red or black.  On 4-wire fans, the yellow wire is PWM speed command.  Look closely at the plug attached to the fan, that all the metal pins are pushed completely into the plastic housing.

duplicate deleted--dunno what happened, I only clicked once, it entered twice

Hi, The Old fan was definatly at fault, the blades were scraping the housing. I have checked that the red, black, and white wires are in the right order but I have noticed that the plug is of a slightly different design to the old one. I reported this to Upgrade Options and they have assured me that it is the correct fan for my Dimension 2350. I think I could file off the offending protrusion but this would make my warranty non valid.

 

Dave 

Hmm.  If the fan is running, the outside pins (red and black) are definitely making contact.  One can generally count on Dell spare parts to fit, but not unconditionally.

 

Warranty on the fan?  It's only 90 days.  A fan that works properly will always work properly for the first 90 days.  But at this point we don't know it's working properly.  I'd call back and say the replacement part causes an error that wasn't there before, get them to ship you another one.

 

If the replacement does the same thing you can 99% eliminate the fan itself as the cause.

Thanks x_lab rat and others,

 

I'll give them another call on Monday and ask them to explain the different looking connectors. I'll just bet they have some glib answer down pat as I can't be the only one to have the problem. LOL

 

Dave

:smileyvery-happy:

One of the problems with Dell 'phone technicians' is that they don't have anything down pat--most notable shortcoming, hardware diagnosis.  Most don't even listen to what you say, beyond picking a keyword out of it and entering that in a search engine then reading back what the search engine says.  It won't have an entry for "replacement part plug doesn't fit", at which point the person on the phone either puts you on indefinite hold or makes something up (the glib part).

 

However, if you can get across to them the simple notion that the 'replacement part doesn't work' or 'fan causes error message' they should be able to conclude you need another one.  Unfortunately, if the search engine shipped you the wrong one last time, it will very likely do so again.