Recommendations for a low starting voltage 92mm fan?

[your_trusted_friend]

Hello guys/gals 

 

As the title says i'm in search of a low starting voltage 92mm fan to replace a broken one on a prebuilt machine from HP. There is a 3pin fan header on the motherboard and its apparently voltage controlled for speed.

 

Low starting voltage is required since the motherboard gives out very low power on boot and if the fan does not spin the bios freaks out as it decides there is no fan connected at all.

Also thermal performance isn't that super important here since it is running as a headless server with low load, but quietness is very much appreciated.

 

My thanks beforehand for any suggestions :) 

[geo3]

https://noctua.at/en/products/fan/nf-a9-5v

[your_trusted_friend]

14 hours ago, geo3 said:

https://noctua.at/en/products/fan/nf-a9-5v

Thanks for the recommendation, but i'm like 99% sure the original Foxconn fan was also a 12v one and i'm afraid the mobo might break that one if it ramps the volts too high

 

If the Noctua warning about that is realistic i mean  

[LogicalDrm]

6 hours ago, your_trusted_friend said:

Thanks for the recommendation, but i'm like 99% sure the original Foxconn fan was also a 12v one and i'm afraid the mobo might break that one if it ramps the volts too high

 

If the Noctua warning about that is realistic i mean  

Do you have some actual reading on pins? Because standard for ATX fan connector is 12V. Server mobos may have 24V headers. Also starting voltage varies between fans, but 5V is usually what they need to start up. If mobo gives out less, header is faulty and you should use direct connection to PSU instead. You can get resistors if noise will be issue.

[your_trusted_friend]

1 hour ago, LogicalDrm said:

Do you have some actual reading on pins? Because standard for ATX fan connector is 12V. Server mobos may have 24V headers. Also starting voltage varies between fans, but 5V is usually what they need to start up. If mobo gives out less, header is faulty and you should use direct connection to PSU instead. You can get resistors if noise will be issue.

 

Sadly i don't have any direct measurements from the pins but i'm sure its just a normal 12v header. Its just the fact that the HP bios is absolute crap and probably feeds just enough voltage to the fans that the original Foxconn fan required.

 

I tried using a 12v Noctua fan that i had lying around and it refused to spin at start, but i could ramp it up very high with Speedfan when booted so that's also another reason why i think its a normal 12v one.

 

I cant really connect it directly to the psu since the bios requires a confirmation prompt if it does not detect a case fan from the header, and as a headless server its something that isn't really optimal.

 

edit: also being a HP bios you cant change any fan settings or auto override the warning from the bios setup.

[LogicalDrm]

2 minutes ago, your_trusted_friend said:

 

Sadly i don't have any direct measurements from the pins but i'm sure its just a normal 12v header. Its just the fact that the HP bios is absolute crap and probably feeds just enough voltage to the fans that the original Foxconn fan required.

 

I tried using a 12v Noctua fan that i had lying around and it refused to spin at start, but i could ramp it up very high with Speedfan when booted so that's also another reason why i think its a normal 12v one.

 

I cant really connect it directly to the psu since the bios requires a confirmation prompt if it does not detect a case fan from the header, and as a headless server its something that isn't really optimal.

Ok. Since its OEM board, there's probably some preset fan mode that prevents booting boost (fans go to 100% and back down) which can annoy some people. Or it might be for something else, like showrooms where you don't want it to sound like jet engine to sell more of them.

[your_trusted_friend]

woops forgot to quote

Edited August 21, 2019 by your_trusted_friend

[your_trusted_friend]

9 minutes ago, LogicalDrm said:

Ok. Since its OEM board, there's probably some preset fan mode that prevents booting boost (fans go to 100% and back down) which can annoy some people. Or it might be for something else, like showrooms where you don't want it to sound like jet engine to sell more of them.

 

Yeah it doesn't really ramp up working CPU fan that much when it starts so i guess so. Too bad the bios is so locked down  Unless there is some weird jumper settings or something idk.

 

Here's the motherboard if there's anything helpful there  

https://support.hp.com/sk-en/document/c03132942