HP 800 G3 SFF Error 90E after PSU change

[Tempak]

Hi.

HP 800 G3 comes with 180W max PSU, which seems to be not enough thinking about additional low-profile graphic card like RTX 3050, which requires at least 300W PSU.

That's why I wanted to buy 400W PSU (942332-001) but unfortunately I bought (L76557-003).

It works, but there is following error on every boot:

"90E-Power Supply fan is not connected or may have malfunctioned"

This 400W PSU does not provide all 7-pin connector cables, and looks like this:

If your PSU P2 connector looks same it means that this PSU does not have fan with FAN_TACH output. FAN_TACH output should be connected to following pin #6:

When mainboard does not receive signals from PSU at FAN_TACH pin, then it warns that most probably your PSU fan is not spinning. There are a few ways how to workaround this, but unfortunately this warning cannot be turned off by BIOS settings.

You can read how to solve 90E at:

https://www.instructables.com/Use-ATX-PSU-With-HP-Motherboard-That-Uses-Propriet-1/

I personally made fake fan NE555 based circuit, described here:

https://www.techidiots.net/project-pages/fake-fan-sensor

I used 1.8k resistor instead 5k potentiometer. Circuit is powered from 12V DC taken from unused, additional PSU connector, and everything works fine. No more 90E errors.

Most probably easier way to solve 90E is connect TACH output from CPU fan to pin #6 of P2 connector, but I choose another aproach, and all I wanna say, yes it works fine.

Regards, Tempak.

[NonSequitur777 · Accepted solution]

@Tempak,

Welcome to our HP Community forum!

That is a lot of effort to battle HP's proprietary power supply challenge!

I would recommend getting a 500-watt power supply with p/n: L77487-001 / L77487-003 / L89233-001, making sure that the whatever 500-watt PSU you buy has a fully populated 7-pin "P2" power supply connector, such as this eBay purchase option shows: For Z2 G5,280 G8 Pro Power Supply,500W,L77487-003,L89233-001,DPS-500AB-51 A | eBay.

Kind Regards,

NonSequitur777

[Tempak]

Yeap, you're right. But I made a post for those who end with PSU like mine and want to get rid of 90E error.

I was searching the Internet a while to find vaild solution, thus I wanted to share confirmed solution.

It's not trivial, and require some basic electronic experience, but it's possible and works fine.

May be an option for someone, especially that in my opinion PSUs with 3-cables only are cheaper than full featured 7-cables.
Here is my fake FAN_TACH circuit looks like.

Regards, Tempak.

[NonSequitur777]

@Tempak,

Your outstanding input is very much appreciated -just like you, I too like to tinker around and see how far I can push the proverbial envelope!

Kind Regards,

NonSequitur777