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Fan speed sensor problem/question

2424 Views 8 Replies 3 Participants Last post by  UncleMacro
Hi all---On my mobo is a 3-pin connector that is labeled "sys fan". When I plug a 3-pin 12Vdc 3-wire fan in to this connector the fan will not even spin. There is also a 3-pin connector labeled "sys fan1". When I plug same fan in to that connector, the fan runs just fine. My question is why will the fan speed not appear on any of the software I run, like SpeedFan and others. From what I gather from the mobo manual, this is a Winbond Monitor Chip W83697HF, and should be capable of detecting CPU fan speed ( which it does) and sys fan speed (which it does not). Thanks for the help and input. :4-dontkno
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There are plenty of motherboards which can only monitor the fan speed on some of the fan connectors. Newer motherboards can almost always monitor the CPU fan for safety reasons but sometimes they can't monitor some of the other fans. I haven't actually checked but I've always assumed it was because some of the sensor chips have a small number of fan inputs so the motherboard can only monitor the important ones. What motherboard are you running?
Do to budget restraintsI am using a Jetway P4X400DBP.
nothing wrong with budget restraints, we all have them in some form or another.

and jetway boards aren't as bad as people seem to say.
Good to know. Anyway, why then, will the software not detect system fan rpm? Like I said, I thought this mobo was capable of cpu and sys fan detection.
Thanks for the help and input. :4-dontkno
According to your manual only CPUFAN and SYSFAN have RPM monitoring. If you look at the PC Health Status screen in your BIOS you'll see that only those two fans have RPMs listed. SFAN1 doesn't have any RPM field listed so presumably it can't be monitored. As for why SYSFAN doesn't work I don't know. I can't see any way to disable it in the BIOS. You might just look at the motherboard for a physical problem and make sure that a metal standoff underneath the motherboard isn't shorting something.
Thanks for the help. I don't see anything amiss with the mobo. Maybe it's the overall budget board after all, huh? :rolleyes:
A late reply

Uncle Marco, if the mobo was shorting on a standoff someplace wouldn't more then a SYSFAN monitor not be working? Also, I e-mailed Jetway tech support and to my surprise, I received a prompt reply! Tech support seems to think there may be a problem with the mobo. But if that is all that this mobo is doing wrong right now, I'll be damned if I am going to swap it out now! If it makes ANY KIND of other show that it has a problem in the near future, then I will. However, I do have a degree of trust in this mobo. In this day and age of technology, it's fairly rare to have a really messed up circuit board. Thanks for the help, opinions, and input.
Uncle Marco, if the mobo was shorting on a standoff someplace wouldn't more then a SYSFAN monitor not be working?
You'd think so but I've seen folks whose various obscure symptoms ending up being a standoff touching the bottom of the motherboard. It doesn't always cause a shower of sparks (although sometimes that's fun to watch - it makes a great story). I was just listing the only thing I could think of to check which you could fix. I wouldn't RMA the motherboard over something minor like a bad fan connector either but I'd check that all the other devices on motherboard (serial ports, parallel ports, USBs, audio, etc.) are working properly.
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