Help with Dell system (detection of system fan)

[OuTpaTienT]

Ok, let me start with this: My boss is an idiot.

He upgraded his processor in his Dell machine, which was unauthorized thus voided his warranty. So now I'm stuck with working on his machine.

The case fan failed, so I replaced it, no big deal, right? It works and *almost* everything is fine. Problem is, during boot-up the Dell bios gives a big "WARNING! System fan not detected!" How can I either make it detect the fan or not issue this warning?

There's not an option for this in the very limited options in the BIOS. And it is a 3-wire fan (pos, neg, rpm?).

Thanks for any help anyone can provide.

[flash4master]

im not sure but i think a three wire conection is pos,rpm,neg. not sure about why it wont detect it.
chris

[brandon184]

If you use a 2 PIN fan, then most likely you won't get the error.

- Brandon

[OuTpaTienT]

Tried that, same error: No system fan detected.

[socalgal]

Have you tried a different/another fan?

[OuTpaTienT]

Kinda. The CPU fan is also a 3-wire. I tried plugging in the CPU fan where the case fan normally plugs (and just plugged the case fan right into the power supply), hoping that would alieviate the problem. But no.

And even though it's not my money, at $15+ a pop, I don't want to purchase any more of these fans than is necessary. Plus, like I said, this one works fine, it's just the Dell BIOS is expecting to see SOMETHING else...what I don't know.

[OuTpaTienT]

For anyone that's interested:

Remember my very first (& probably most important) point: My boss is an idiot.

Ya see, what he did was have someone else upgrade his CPU from a PIII/450 to 700. And when they did this they powered the CPU fan by splicing the wires into the system fan. Best I can figure, there was no CPU fan before his upgrade. Dell has these special moldings to channel airflow over the CPU by using one of the 2 exhaust fans (aka system fan).

So then, when the system fan failed (more on this in a sec) my boss, aka the idiot, calls Dell to have someone come fix the machine. Duh. So the guy is working on the machine, and when he notices the amateurish rigging that's been done the very first thing he does is call Dell to report the status, THEN he tells us about the problem and he can't work on the machine and the warranty is voided.

So now I'm left to fix the machine, which I don't HAVE to do but I'm still kinda new there and it wouldn't hurt to impress the boss by fixing his machine. The alternative is he will have his "consultants" come fix the machine at $75+/hr.

This has all happened this week, while my boss has been on vacation in Europe. He's back on Monday, so I got till Sunday to fix this.

About the system fan: Naturally I didn't toss his old case fan that supposedly failed, I brought it home. Dusted it off. Rewired a connector to it. Hooked it up to my machine (which btw, gave me a total of 8 fans!) and it has been running just fine for two days now. So obviously the fan didn't fail. I guess it was that ****-poor wiring job the previous guys did. They didn't even use electrical tape on their splice. They used cloth tape, ya know, like you'd normally use on a bandage dressing. Geeez. Personally I would've soldered the wires and used shrink-tubing to seal it. Well no, actually I wouldn't have spiced them in the first place, especially since the Dell bios is sensing more than just RPMs on that circuit. I believe it's sensing the difference in current...because the original fan is 0.69A and the replacement fan is 0.17A (quite a difference).

Anyways, I guess I'll see if I can put this system fan back and just wire the CPU fan directly from the power supply. And return the new fan or maybe just add it to my collection of fans. http://sysopt.earthweb.com/forum/wink.gif Hopefully that will fix the situation.

[socalgal]

Any luck, OuT?

[OuTpaTienT]

(dang! http://sysopt.earthweb.com/forum/wink.gif) Alright, here goes:

The reason it wasn't detecting my fan was so obvious I over-looked it. When plugging the 3-wire fan into the motherboard, the 3rd contact was being pushed out of the plug by the m/b pin. er.....doh!

So, that was an easy fix. The Dell machine was happy with the 3-wire CPU fan plugged in the m/b. I connected the exhaust case fan directly to the power supply. That way, he'll get an instant warning should the CPU fan fail. And if the case fan fails, then it might get warm in there, but the CPU won't fry itself. Plus the system will shutdown when it becomes too warm in the case.

And come Monday I'll have to thoroughly enjoy any praise I get because I'm normally so bad at brown-nosing, plus I'm utterly unwilling to suck-up. I have no qualms at all about disagreeing or challenging those above me. Sometimes it gets me in trouble, other times it earns some respect.

So that's my story. http://members.home.net/autpatient/silly.gif

[socalgal]

Glad to hear you solved it, and that it ended up something simple. http://sysopt.earthweb.com/forum/smile.gif

As for Monday... put on your Tech Wizard cap and enjoy. http://sysopt.earthweb.com/forum/wink.gif