System Fan Error 90b

[as1471]

Hello, I have HP Pavilion Desktop 570-a100na. Windows 10 64bit.

For the past 2-3 weeks on start up I sometimes get system fan error 90b.

How do I test the system fan to make sure that it is faulty and needs replacing? I have already opened the case and cleaned the dust away. Bios is saying up to date.

I phoned HP support and was informed I need to buy heatsink hp desktop pc 570, 644724-001 and I can buy this from amazon. I will be using amazon. co . uk site.

Could someone double check this is the correct system fan to buy before I go ahead and order it (and give me a link to best one if possible). Where is the system fan located on the machine please? Is there more than 1 fan?

Also, will I need to add thermal paste or anything like that or is it simply a case of unscrewing one fan and installing a new one? If I need to add thermal paste how do I go about it please.

I have never had to do anything like this before and I don't want to mess it up. Thanks for any help.

[Bill_To]

Hi

You should be able to replace the CPU fan with a similar sized 4 pin static pressure fan if the fan is removable. The fan could be a 80 mm or 92 mm fan. No details on fan size at Amazon. No CPU fan dimensions are provided by HP at the support site for your PC.

Your PC would have a CPU heatsink/fan located on the MB. You would also have a rear chassis fan.

The part referenced  644724-001 is a CPU heatsink/fan combo https://www.amazon.com/Jingelmall-Replacement-644724-001-724801-001-644725-001/dp/B098BMY164/ref=sr_... . You don't need a heatsink.

Check the fan for a part number. Maybe you can buy the fan. The fan may not be removable which will require fan/heatsink replacement.

Your MB is detecting a startup problem with the fan. Is the fan running when the PC is active? How are temps?

The fan could be failing to rev up at system startup or the MB sensor is giving false readings at system startup.

The Amazon heatsink/fan part number matches HP's replacement part recommendations.

You will have to clean the CPU and reapply thermal paste to the CPU if you have to replace the heatsink. 

[as1471]

Hello Bill To,

Thanks for reply. If it was the CPU fan which was faulty would it not have said "CPU fan error" instead of "System fan error (90b)"?

The CPU fan doesn't seem removable.

I opened the case and the CPU fan and rear chassis fan were both running. I downloaded Speedfan, it was unable to detect any fans (due to incompatible motherboard?). However the temps seemed okay.

The 90b error message is intermittent if it continues I will take it to a repair shop to be looked at.

[as1471]

Hi, so the system fan error 90b is continuing.

Am I right in thinking the fan HP support told me to get (644724-001,CPU heatsink/fan combo) is the wrong one and I in fact need to order and replace the system/rear chassis fan instead? I think I should be able to replace that by myself.

[Bill_To]

Hi

Sorry about the delay. Never got a notification when you replied to this thread on 2-22-23

Yes, you are correct. The system fan is a chassis fan.

You don't need the CPU heatsink/fan replacement part. I wish HP would provide fan error specificity. A system fan error message is ambiguous.

[as1471]

I looked on HP PartSurfer and I need this one. 859086-001, FAN SYSTEM 9225 2500RPM AXIAL, SHAVE2

Searched the web for it and only place that had it was impact computers in USA. Not an option for me as I am in UK and it said estimated shipping $56.

Someone be so kind as to give me a link to an alternative compatible one please. Thank you.

It is 3 pin. 

[Bill_To · Accepted solution]

Hi @as1471 

You can use any similar sized fan (92 mm or 80 mm) as a replacement part. A PWM four pin fan will work. Both types (three pin/four pin) should connect to the fan header.

The catch is: your MB might display a fan error at startup when using a retail fan.

The opinions or troubleshooting suggestions in this response are my own. I am not: employed by or associated with HP, Inc.