fan running full speed

[JJR]

I have just had a laptop come in with the fan running at full speed (very loud).
The client says his son had it in the far east where a chip had been replaced on the motherboard, doesn't know which chip, doesn't know why.
It's a HP Pavilion G6-1103sa. I had a look at the board and noticed a chip (APL5606) had pins 2&3 solder bridged. I cleared the bridge and the laptop now works perfectly.
Question - would you deliberately bridge pins 2&3 on a fan regulator to make it spin at full speed? If not could the tech have replaced the chip and just done a bad solder job?

What do you think?

[JJR]

Re: fan running full speed

Data sheet for the ALP5606 -

[keeney123]

Re: fan running full speed

Why it is bridge really does not matter. The fact that it is connected in a way that the designer had not intended is call for alarm. I think you need to undue this short and then we will be able to tell if it is simply a mistake or if there was a problem the technician could not fix because he had a problem he could not fix for what ever reason.

[diif]

Re: fan running full speed

Does the ALP5606 look like it was soldered on by a drunken half blind monkey ? If so it's probably a mistake. If the rest of the soldering looks neat it possibly a quick bodge to keep the fan faster and the laptop cooler (perhaps the original complaint/possibly it didn't have anything replaced at all).

[JJR]

Re: fan running full speed

The chip was positioned perfectly square and all pins looked professionally soldered, with the exception of pins 2&3.
The bridge was a large blob of solder (sorry, no pics) that I would think was impossible to miss if the work had indeed been done on that chip.
So I'm thinking it must have been a bodge, but why, when the blob was removed everything was fine.

Probably one of those unanswerable questions.

[diif]

Re: fan running full speed

Pin 2 is voltage in 4.5v-6v and pin 3 is voltage out, so effectively the chip and it's control has been bypassed with more than normal voltage sent to the fan. I think the fans are only 5v so it much have been screaming ?!

[JJR]

Re: fan running full speed

Yes, it was very loud, the client had lived with it for a couple of months and reckoned it was making him deaf!
While the fans was running permanantly flat out the CPU temp was 34c, once I removed the short it was running at 49c and upto 57c when the fan kicks in.

[diif]

Re: fan running full speed

I don't know how people can do bodges like that and be happy with themselves.
At least it did the job I guess, lol.

[jasko_jacker]

Re: fan running full speed

usually on some laptop as some hp models , the heatsink is not adeguate due to some bga (gpu or others) costruction issue. to prevent bga damage some technicians short two pins to change fan speed at maximum. If you remove this hack, it's possible to have a bga problem.

[keeney123]

Re: fan running full speed

Yes, it was very loud, the client had lived with it for a couple of months and reckoned it was making him deaf!
While the fans was running permanantly flat out the CPU temp was 34c, once I removed the short it was running at 49c and upto 57c when the fan kicks in.

Is the fan maintaining the temperature under 57C? Sometimes if the fan is set to passive cooling instead of active cooling the HP seem to over heat. HP defaults out to passive cooling. This can be changed in the control panel in power plans. I also believe it can be changed in the bios.

[JJR]

Re: fan running full speed

usually on some laptop as some hp models , the heatsink is not adeguate due to some bga (gpu or others) costruction issue. to prevent bga damage some technicians short two pins to change fan speed at maximum. If you remove this hack, it's possible to have a bga problem.

This is possible as a lot of HP laptops were susceptible to overheating, but I have not come across a remedy like this before.

[JJR]

Re: fan running full speed

Is the fan maintaining the temperature under 57C? Sometimes if the fan is set to passive cooling instead of active cooling the HP seem to over heat. HP defaults out to passive cooling. This can be changed in the control panel in power plans. I also believe it can be changed in the bios.

When the temp reached 57c the fan activated, when it dropped to 49c the fan stopped. The BIOS had the option to run the fan permanently, I disabled this option.

The client is now happy and has taken the laptop away. We wait to see if it ever returns

[keeney123]

Re: fan running full speed

When the temp reached 57c the fan activated, when it dropped to 49c the fan stopped. The BIOS had the option to run the fan permanently, I disabled this option.

The client is now happy and has taken the laptop away. We wait to see if it ever returns

I would had enable that option as I have heard from more one than person that their units had overheated which cause the processor to fail. I actually work on one that was putting out a lot of heat and enable the fan to run actively. This then cured the heat problem. I also made sure that the minimum processor was set to around 5% to allow it to cool off when not in use or in a lower state of use.