HP Vectra VL400 PC - Power Supply fan error

[Edsel Delmiguez]

I am upgrading to a new non-HP power supply with a 350 W rating. I have a mini tower. The power supply does not have the P8 power connector which comes out of the original HP power supply and connects to the motherboard. Consequently, upon boot up, it runs into a "Power Supply fan error." How can I disable this feature so that the system board accepts the new power supply? Is there a workaround for this? Thanks.

[Eino V]

Loook at the tread:
http://forums1.itrc.hp.com/service/forums/bizsupport/questionanswe
r.do?threadId=980214

and the last message with attached picture.
Somebody have used 100ohm resistors instead the jumper.

Here is another thread about the same problem:
http://forums1.itrc.hp.com/service/forums/bizsupport/questionanswe
r.do?threadId=986050

[Peter_F]

Hi there,

I am having the same issue and I have followed the instruction as provided in this thread....must say thanks for the info!!But I do have some questions - how does this circuit work and why by just bridging two pin does it "fool" the bios post and also does this cicuit keep checking for the fan (RPM????) when the PC is running? Also as this is a hack will it cause damage to the board? I am interested as I intented to run this PC 24/7 as a firewall.

Thanks heaps

Peter

[Eino V · Accepted solution]

My opinion is, that it is best to use the same resistance there as the original fan has to fool the computer believe, that the fan is installed.

[Rich S]

It makes sense to place a load on the jumper in order to fool the logic of the system.
My HP didn't require that. I just left the fan sensor disconnected. There is a shut off within the PS, so there shouldn't really be a monitor within the MOB logic. Must be for warranty purposes.

So if you do bypass this logic, I would not worry about it. The new PS will shut down if overheated or overloaded.

If you have the old PS, you might wish to check the load with a VOM and verify the 100 ohm amount. If you do not have the old PS or it is non functional, I would try the links suggestion.

either way, please post your findings and results here.

Rich

[Rich S]

I would NOT do a direct short as the one link suggested. That could harm the circuit. I would measure the old PS load and match it with a resister at the least.

see:

http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=602321

Rich

[Edsel Delmiguez]

I measured the resistance across the +12 V and the sensor lines from the PS. I got 10.23 K ohms. I then jumpered the motherboard with a resistor measuring 9.98 K ohms. It didn't boot successfully, so I replaced it with a 100.5 ohm resistor. The motherboard was then successfully fooled. The PC is now running smooth. Thanks.

[Rich S]

That would make sense. If you had a sensitive enough meter and turned the fan while measuring it, you would have had a variable load. 100 ohms is enough of a constant load to full the MOB.

Great work.....and glad to hear all is OK.

Rich

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[Peter_F]

Hey there...

I have also used a 100ohm resister to jump the pins for the PS Fan and it has worked without issue!!

(I created a small PCB to make it neater!!)

Thanks for the great advise......

Peter F

[Rich S]

Glad all is working out....

E=IR or more R=E/I.. :)

Rich

[Rich S]

Sorry, should have explained the E=IR...

see :

http://www.aikenamps.com/OhmsLaw.htm

:)

Rich

[Eino V]

Hi Edsel
Fine to read that you have solved the problem. The resistance of the fan varies according to the fan speed. 100 ohm is likely near the resistance of the original fan, when it is running.
Eino

[Edsel Delmiguez]

I also made a small pinkie-sized PCB for the resistor. It looks neat. Maybe adding a diode in series would not be a problem. Many thanks.

[Rich S]

A diode changes AC to DC or acts as a filter in DC. An LED (which is a diode too) would be nice. I've been meaning to buy some blue ones.

Glad all is working out for you....


Rich

[Peter_F]

Hi Edsel...

I had the very same thought re the diode.....Must say I'm not an electronics wiz but was advise to maybe us a Zener Diode in series so as to act as overload protection. Was not sure how to get the correct rating.......

Regards

Peter

[Rich S]

No a fuse would act as protection.
The original circuit I am sure is adequate. All that was needed though is a load to fool the motherboard. The original fan has a circuit that would send the signal to shut off if overheated.

There are a lot of great electronic classes out there. Even the basic TTL (transister logic) classes would open your mind up to the fundementals of electrical design.


Rich

[Edsel Delmiguez]

Hi everyone. Yes, I was referring to those LEDs. I thought it would look nice if the PCB could indicate, through the diode, that the circuit is complete. Thanks again. :o)

[TMH SE]

Just posting to thank everyone here for their posts on this subject.
One of our 3 Vectra machines died over Christmas, power supply gave out.
Having substituted a PS from another of our 3 Vectra machines to verify that I was reading the beeps correctly when trying to boot the dead PC, and it booted perfectly fine, I then went loking for a new PS for it.
No such luck ! I was unable to find a PS, new or used, that had the fan sensor wire fitted other than from HP at about £80 !
I could buy a whole new PC for less than that !

I searched the net for a solution and found myself on this site, read the info' here and followed some of the links to be sure I picked up all I needed to know, bought a replacement PS without the fan sensing wire, followed the advice here and jumped the 2 pins nearest to the power input on the MB with a 100 ohm resistor, I used the old lead cut from the old PS which meant I didnt have to mackle a way to plug the "hack" in, booted first time without any problem and is now running like a dream again.

Even though it is 5 or 6 years since this thread was last added to, the information is still very useful, your help has been invaluable, thank you all very much.

regards
Tim

[isend]

Hi @Eino V , 

I have the same problem on my VL400, but the ITRC links you provided are obsolete. Do you still remember the wirings in the picture from those links? I guess I am supposed to put a resistor between the center pin and a side pin (which one?) of the 3-pin fan connector, and then connect two pins (which two?) of the fan connector to the two pins of the PSU power connector (Which two? The furthest two from the 4 pins of the 20+4 pin PSU power connector?).

Is my guess close to the correct answer? Thank you.

[Eino V]

Sorry, I don't remember it anymore and I have not either VL400 anymore. It has gone too long time since I gave that advice.

[isend]

@Edsel Delmiguez @TMH SE @Peter_F Hi, sorry to bother you guys, but does anyone of you still remember the wirings to solve the problem? I guess I am supposed to put a resistor 100 ohm between the center pin and a side pin (which side?) of the 3-pin fan connector. Then do I also need to connect the fan connector to the PSU? Thank you very much.

[Edsel Delmiguez]

The fan connector is actually located adjacent to the motherboard power supply connector. You should disconnect the old power supply from the motherboard. Just jumper the 100-ohm resistor across the 2nd and 3rd pins of the 3-pin fan connector. You can actually use the 3-pin fan connector from the old power supply. Just cut the old connector from the old power supply. Leave about 20 millimeters of wires hanging out from the 2nd and 3rd pins and then solder the legs of the resistor across the pins. Make sure yiu use some shrinkable insulating tubes and you should be good to go!

[isend]

@Edsel Delmiguez  Thank you so much! Your instruction really saved us!

[Edsel Delmiguez]

You're welcome, @isend!