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05-27-2018 08:41 PM
On booting up I get the mesage 511 CPU Fan not detected
Press F1 to boot
The fan twitches a few times and then will start before pressing F1 if I wait about 15 seconds. On pressing F1 the desktop boots OK and the fan continues to work (RPM is about 1550).
The fan has been cleaned and I tried disconnecting and reconnecting, and I disabled Fast Boot all to no avail.
The Bios is the latest.
I've seen another old thread on this where the best solution seemed to be to replace the fan. Is that still the case or is it a software problem?
05-28-2018 05:40 AM - edited 05-28-2018 05:47 AM
The fan warning is a precaution so the user does not continue using the PC as it will result in a failure of the CPU if the fan fails to start. Replacing the fan is the best solution, unless you wish to gamble on the CPU burning up.
BTW: if you replace just the fan, then it is less a problem. If the hear sink and fan combination is removed to replace that, then the thermal paste needs to be replaced also. Clean the old paste off and reapply new thermal paste.
I'm not an HP employee.
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05-31-2018 01:00 AM
I monitor the fans and CPU temps . The most one of the cpu cores has reached is 51 C, but usually they're in the 20's and low 30's so no problem there.
The fan is a Cooler Master DC12V 0.48A 80mm 4 pin connection. It always spins around 1550 rpm but I thought it was supposed to be a PWM type fan with variable speeds.
Don't seem to be any available new ones, only refurbished from dodgy sites in China.
I may get another brand and try it. Ones available have much lower Amp specs and variable speeds some exceeding 1550 rpm. I am a bit puzzeled how lower amps can produce greater RPM.
06-05-2018 03:29 AM
I replaced the fan with a Noctua NF R8 Redux edition PWM 80mm Fan. (Aus $14). The error message is gone and the fan starts immediately the power button is pressed without any twitching. Its Amperage specs 0.06 Amps are a lot lower than the Cooler Master so it's either more efficient or the HP Cooler Master never needed 0.45 Amps. The Cooler master was spinning at 1550 rpm whereas the Noctua spins at 650 rpm and maintains the same CPU temps. I have still to see the PWM ability as the Noctua has a top speed of 1800 rpm. I may still have a problem that is not allowing the PWM to function correctly. I hope not.