512-rear chassi fan not detected

[Dickie-07]

There hard to mix up the CPU fan conector is right at the front right under the CPU fan so no they are not mixed up tks

[mdklassen]

> They're hard to mix up. 

But not impossible -- that is why I asked.

> The CPU fan conector is right at the front right under the CPU fan.

Good. Now, verify that the rear chassis fan is connected to the connector labelled "chassis".

Is there more than one connector labelled "chassis" ?

> So no they are not mixed up.

Good.  Got another system with the identical motherboard? 

Can you pull the chassis-fan from that other system, and connect it to the "bad" motherboard?

[Dickie-07]

The rear chassis fan is in the power supply so all I would be doing is exchanging power supplies?

[Dickie-07]

I'm thinking you don't know much abput HP 8000 and 6000 series desktop computers can you pass my inquires on to someone who is fimaliar with the product!!!

[mdklassen]

> can you pass my inquires [sic] on to someone who is fimaliar [sic] with the product!!!

Sorry, but I am not now, and never have been, an employee of HP.

Therefore, I cannot oblige.

Usually, the "rear-chassis-fan" has a 3-wire cable to the power-connector labelled "chassis" on the motherboard.

Normally, the fan inside the power-supply draws its own power -- not needing a "loop-back" connection.

[mdklassen]

From page 1 of: http://h10032.www1.hp.com/ctg/Manual/c01883661

and on the same page:

where CHFAN2 supplies power to the REAR CHASSIS FAN assembly, not to the fan inside the power supply (not shown).

[Dickie-07]

(where CHFAN2 supplies power to the REAR CHASSIS FAN assembly, not to the fan inside the power supply )

the CHFan2 connection is not used in this application as the rear fan is power by the main power supply(white 4Pin)above it

[mdklassen]

> the CHFan2 connection is not used in this application ...

But the BIOS settings have enabled the motherboard to check that connection, and so the error-message is generated, because nothing is connected.

As an "experiment", temporarily connect a chassis-fan to that CHFAN2 connector, and reboot, to see if the error-message is still produced.

[Dickie-07]

ok I just happen to have one I'll have to wait as I;m running HP system check from the support down load page it says the system board is good it was the first test I ran 

[Dickie-07 · Accepted solution]

YES that worked no more messages and direct boot when I down loaded the BIOS update it must have been for a full size desktop with a rear fan not a SSF 8200 elite now how do I get back to the orginal correct BIOS i notice when I installed the update it stored the old BIOS somewhere how do i find it and reinstall .Thank you so much now we know what the problem is it should be an easy fix I await your instructions sorry for doubting you but you didn't seem fimiliar with the product ie fan was in the power supply and HP blocking BIOS on their business computers once again I appoligize!!!!!!Thank you for bearing with me I was just getting frustrated.