Dell OptiPlex 755 SFF Rear HDD Fan Press F1 Error FIXED!

Question

EDIT: Fix for F1 error is on post #2. Only try this if you know what your doing and don't mind not having a stupid HDD fan. I now only use a SSD and it needs no noisy power wasting fan. ORIGINAL POST: I have removed the dying hard drive fan on the Dell Optiplex 755 SFF (fan is built within a hdd cage) and modded the side of the case to include a 120mm Yate Loon fan. I removed the hard drive cage in its entirety and then used the free space where the floppy drive used to be to place my 256gb SSD. The system is much nicer this way and now there is room for the 120mm fan (already modded). However, at boot there is a rear fan error and it asks you to hit F1 to continue. It goes away when I connect the old dying noisy fan (there is no longer any room for it). Since I no longer want the hard drive cage (or its fan for that matter) and I can not put this fan back in, I want to use the connector and wires from the old dead fan and connect them to my nice new Yate Loon, which is the ideal cooling solution (used as an intake fan). The color codes are: Yate Loon (D12SL-12): Red=12v, Black=Ground, Yellow=Tach (I think) Dell HDD Fan (AVC BN06015B12H): Red=12v, Black=Ground, Yellow? Blue? (Either PWM and/or Tach) What are the Blue and Yellow for on the Dell HDD fan? Can I just connect the Dells Red wire to the Yates Red, and Black to Black? This should give me a working 12v fan, however I am wondering if the Yate Loons left over Red wire could be used for sensor. Any help would be great. Really sad that Dell did not include a ignore fan setting within the bios. Thank You! SkOrPn  EDIT: Ok, the Yate Loon does not turn on when connected to the fan header. What is missing? The old Dell fan is rated 12v 0.36A and the YL is 12v 0.30A, less than the old fan so the fan header would seem like the logical place to get the required power since it provides plenty. When the old fan is connected it is providing 12v, but does not provide any power when the Blue and Yellow wires are missing? EDIT2: Ok, figured out that the Yate Loon fan uses the Red wire as the 12v (Somehow I thought it was Yellow). I now think the Yellow must be a tach wire for RPM. Now I am wondering if the Dell system can monitor the RPM by connecting the yellow wire without any harm to the system without the blue connected. In fact, I wonder if the controller just monitors RPM to warn of the fan failure. If so, maybe I can connect the Yellow and get rid of that BIOS screen error at bootup.

marcgpx1 · Accepted Answer

Hello I have linked yellow wire pin from HDD fan connector to yellow pin from CPU fan connector and no more F1 fan error at boot :emotion-2: - fixed i dont need loud hdd fan for my SSD disk.

speedstep · Answer

There is more than Tach there is also a thermal sensor and its proprietary.  It will NOT work with non dell fan.

speedstep · Answer

Its not a simple passive circuit.  No I don't know the color codes. It absolutely is not 'standard'.

SkOrPn · Answer

Thank you for your response.

Do you know the color codes for the tach and thermal sensor wires? The fan is already connected and working great on that mobo header. However if the old fan uses the industry standard two pulses per revolution than the tachometer should still work just fine. I do not expect nor am I wanting to use the thermal wire, so it can and will be omitted.

Thanks again

SkOrPn

Italianjob · Answer

Yes! It works like a charm. MARCGPX1 you are my hero! Thanks from Italy.

SkOrPn · Answer

Yes agreed, it worked perfectly. SpeedStep was wrong, it is standard fan pinouts and a standard sensor type, but using a proprietary connector of course. So you can use these pin outs for your add-in fan or to bypass the F1 error. I used the yellow in the same fashion as MARCGPX1 and it got rid of the F1 fan error immediately. Now my system runs much cooler, 10C cooler on the CPU alone and much quieter thanks to my simple modding. Its funny how us DIY modders at home can do things better than paid engineers.

Funny thing is, Dell forums did not send me a notice of reply to this thread until 10/12/2014 (today) over 1 year later.

Thanks MARC

henrik14 · Answer

Thanks to marcgpx1 for the inspiration! The trick/solution also works for my Optiplex 755 SFF (maybe using USFF mainboard), so one annoyance less in my life :emotion-5:.  Consider the solution verified! Best regards from Denmark

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