long continuous beep when connecting case fan to only the psu. help please.

[sneakygamer]

hi everyone!

i have a gigabyte ga-z97x-gaming3 motherboard and a cooler master g650m psu.

i have an issue with getting 1 or multiple case fans connected to the psu only.

my case fans have a 3-pin connector and a molex connector attached to that.

when my case fan is connected to the motherboard only i have no issues but i decided to connect it to my psu to free up a fan header on my motherboard.

the issue i have here is when i connect my fan to the psu only with a molex cable and the molex connector on the fan and try to boot my pc it gives me a continuous long beep that only stops when shutting down my pc, also my fans all start spinning but the pc wont start up/get no video on my monitor. (i use integrated graphics so no gpu is installed).

when i connect my fan by molex to the psu AND to the motherboard then everthing works fine just as it did when it was connected to only the motherboard.

i thought maybe the cable was faulty but thats not it since i use it also to power up my front panel led light.

i also thought of other components being faulty but that cant be it either since everything works perfectly fine when the fan is connected to the motherboard only or to the motherboard AND the psu.

the only issue is when trying to connect it to only the psu. anyone knows what might cause this issue and/or how to fix it?

here is a link to the fan connectors and the cable im using to connect it to my psu : http://imgur.com/a/G2brr
one end (the most right end) of the cable in the second picture goes into those female sockets in my psu and all other connectors on that cable are molex connectors.

note:i know i could use a splitter or fan controller to get more fans on my fan headers and i will do that but since i discovered this issue and cant find a similar issue online i want to know what causes it and how to fix it if possible.

thank you all!

 

[DonkeyOatie]

This is the list of common beep codes and their cause.


How to Interpret Computer Error Beep Codes

When the computer makes those funny sound via the system speaker, it's not doing it because it wants to be heard. The computer is trying to talk to the operator/technician and tell them what's wrong.

Beep Codes:

No Beeps: Short, No power, Bad CPU/MB, Loose Peripherals

One Beep: Everything is normal and Computer POSTed fine

Two Beeps: POST/CMOS Error

One Long Beep, One Short Beep: Motherboard Problem

One Long Beep, Two Short Beeps: Video Problem

One Long Beep, Three Short Beeps: Video Problem

Three Long Beeps: Keyboard Error

Repeated Long Beeps: Memory Error

Continuous Hi-Lo Beeps: CPU Overheating

Does this match what you hear?

 

[sneakygamer]

This is the list of common beep codes and their cause.


How to Interpret Computer Error Beep Codes

When the computer makes those funny sound via the system speaker, it's not doing it because it wants to be heard. The computer is trying to talk to the operator/technician and tell them what's wrong.

Beep Codes:

No Beeps: Short, No power, Bad CPU/MB, Loose Peripherals

One Beep: Everything is normal and Computer POSTed fine

Two Beeps: POST/CMOS Error

One Long Beep, One Short Beep: Motherboard Problem

One Long Beep, Two Short Beeps: Video Problem

One Long Beep, Three Short Beeps: Video Problem

Three Long Beeps: Keyboard Error

Repeated Long Beeps: Memory Error

Continuous Hi-Lo Beeps: CPU Overheating

Does this match what you hear?

thanks for the reply!

unfortunately none of these beep codes match to what i hear.

when connecting the fan with molex to my psu and not to the mobo its a beep that does not stop whatsoever untill i force shutdown the pc using the power button on the case.

like i mentioned before, i thought of a component being faulty in my pc, but after disconnecting the molex-connected fan from the psu and connecting it back to the motherboard with the 3-pin connector everything works perfectly fine again. (i have not touched any other component in my pc except the molex cable and the fan molex connector while doing so).

also like i mentioned before, this beep error happens only when i try to connect a fan to only the psu using a molex cable and the molex connector which you can see in the pictures i included in my post.

- when either connecting the fan with the 3-pin connector to only the motherboard, everything works perfect.
- when connecting the fan with the 3-pin connector to the motherboard AND with the molex connector to the molex cable on my power supply, everything also works fine.

Thank you!

 

[DonkeyOatie]

Are you certain that the noise is coming from the speaker?

 

[skippyboy92362]

I've run into this issue myself before and your hardware is probably fine. It's a simple fix. Go into your bios go to PC health status, find CPU, CPU OPT, System Fan Fail Warning, and if there is an option for the system fans disable it. This should solve your problem.

 

[Paperdoc]

skippyboy92362 is right. The mobo monitors all your fans connected to its fan ports to detect failure of cooling. When you connect all your case fans to only a PSU Molex output, there is no fan speed signal being sent back to the mobo. (That signal, generated in each fan, is fed back to a mobo fan port on the Yellow wire of Pin #3.) So, with no fan connected to the mobo SYS_FAN ports it thinks all your case ventilation has failed, puts out a drastic permanent warning, and refuses to start up to prevent overheating.

Now, you have two related issues to deal with. First and IMPORTANT: you should NOT ever connect BOTH the fan's connectors - use EITHER the connection to a Molex PSU output, OR a 3-pin connection to a SYS_FAN port, but never both. Doing both can force power from the PSU into what should be only an output from a SYS_FAN port and risks damaging that port.

Next you have a fan control problem. You have 3-pin fans that require Voltage Control Mode, but all your mobo SYS_FAN ports are of the 4-pin type and your manual indicates they only work in PWM Mode. This means that those mobo ports CANNOT control the speed of any 3-pin fan plugged into them. Such a fan can only run at full speed. But you can get that same result by disconnecting them all from the mobo and connecting them to a Molex power output from the PSU. (By the way, if you buy a couple of Molex power splitters, you can connect all three fans to ONE Molex output - it certainly can provide power to all those fans.) As you have found out that does not work - yet. But skippyboy92362 told you the solution. See your manual, p. 46, for the note about how to disable the System Fan Fail Warnings. NOTE as you do this: it is always useful to have the fan failure warning for the CPU cooler active. So, IF you can disable ONLY the SYS_FAN (case cooling fan) warnings and leave the CPU_FAN warning active, do it that way. Once that is done, the mobo will stop checking for case fan failures and allow normal operation.

IF you want a way to have your mobo do automatic control of case ventilation fan speeds, post back here for further advice. But with what you have, it can't be done.

 

[sneakygamer]

Are you certain that the noise is coming from the speaker?

Yes, very certain, but i see that skippyboy92362 gave me the answer to my problem

thanks anyway.

 

[sneakygamer]

I've run into this issue myself before and your hardware is probably fine. It's a simple fix. Go into your bios go to PC health status, find CPU, CPU OPT, System Fan Fail Warning, and if there is an option for the system fans disable it. This should solve your problem.

Dude you're the man! thank you so much!

i have spent over a week breaking my head over this problem and the fact that i could not find out what the hell the problem was.

unbelieveable that this problem is so easily fixed and that it is caused by just that haha.

i indeed set system fan fail warnings to on because i thought it would come in handy for if my fans should fail one day but i turned it off and tried it and yep, its fixed.

again thanks so much man! i picked your reply as the answer to this thread.

 

[sneakygamer]

skippyboy92362 is right. The mobo monitors all your fans connected to its fan ports to detect failure of cooling. When you connect all your case fans to only a PSU Molex output, there is no fan speed signal being sent back to the mobo. (That signal, generated in each fan, is fed back to a mobo fan port on the Yellow wire of Pin #3.) So, with no fan connected to the mobo SYS_FAN ports it thinks all your case ventilation has failed, puts out a drastic permanent warning, and refuses to start up to prevent overheating.

Now, you have two related issues to deal with. First and IMPORTANT: you should NOT ever connect BOTH the fan's connectors - use EITHER the connection to a Molex PSU output, OR a 3-pin connection to a SYS_FAN port, but never both. Doing both can force power from the PSU into what should be only an output from a SYS_FAN port and risks damaging that port.

Next you have a fan control problem. You have 3-pin fans that require Voltage Control Mode, but all your mobo SYS_FAN ports are of the 4-pin type and your manual indicates they only work in PWM Mode. This means that those mobo ports CANNOT control the speed of any 3-pin fan plugged into them. Such a fan can only run at full speed. But you can get that same result by disconnecting them all from the mobo and connecting them to a Molex power output from the PSU. (By the way, if you buy a couple of Molex power splitters, you can connect all three fans to ONE Molex output - it certainly can provide power to all those fans.) As you have found out that does not work - yet. But skippyboy92362 told you the solution. See your manual, p. 46, for the note about how to disable the System Fan Fail Warnings. NOTE as you do this: it is always useful to have the fan failure warning for the CPU cooler active. So, IF you can disable ONLY the SYS_FAN (case cooling fan) warnings and leave the CPU_FAN warning active, do it that way. Once that is done, the mobo will stop checking for case fan failures and allow normal operation.

IF you want a way to have your mobo do automatic control of case ventilation fan speeds, post back here for further advice. But with what you have, it can't be done.

thanks for the explanation! now i dont only know what the problem was and how to fix it but also why this happens and im all about learning so thats awesome!

"drastic permanent warning" man that it was indeed lol, everytime it made that sound it freaked the living hell out of me because i thought something was gonna catch fire or something haha.

its also good to know i should never connect a fan to both the sys_fan header and the psu at the same time. i figured this was something i shouldn't do but just for the sake of testing if that would work i did it anyway. 2 times tho 🙁 still, it was for very short periods of time so i hope i did no damage. all of my fans are now connected to only the sys_fan headers at the moment and they all still work perfectly so i'm guessing nothing is damaged.

i do know tho that my motherboard cant control fan speeds because of my fans having a 3-pin connector but they dont run at full speed tho, not unless i want them to. i use SpeedFan to control my fans and i can set them at whatever speed i like with that program so i dont mind that they're only 3-pin connector fans. the next 2 fans im about to buy will be pwm-connector fans tho. and as for disabeling the fan fail warnings, i have an option to disable only the warning for the system/case fans. i figured it wouldnt be a good idea to turn it off for the cpu fan so im not doing that.(thanks for the heads up) .

im really interested in having a way to have my motherboard do automatic control of case ventilation fan speeds tho so if you want you may explain this to me. im curious as to why it cant be done tho because of "what i have"?.

Thank you for the lenghty explanation tho! learned alot from it and i appreciate it alot!

 

[Paperdoc]

Case ventilation fans CAN be controlled automatically by the mobo, similar to the way it can control the CPU fan. But it is done by the SYS_FAN ports, rather than by the CPU_FAN port. The principle is the same, however. The difference is that the SYS_FAN ports' control of case fans is based on actual temperature measured by a sensor built into the MOBO by its makers, rather than by the sensor built into the CPU chip.

In each of those two types of automatic control loop, the mobo's software constantly compares the actual temperature as measured by its respective sensor to a target value (the BIOS has a default target value, although some mobos allow you to change that) for that sensor. It then changes the speed of the cooling fan(s) to meet that target. NOTE that really this is a TEMPERATURE control system, not fundamentally a fan speed controller. It just manipulates the fan speeds to accomplish temperature control in each case.

The fly in this ointment is that the design of fans changed recently. Originally all case and CPU cooling fans could be controlled by changing the voltage fed to them, and this is called Voltage Control Mode. It works for 3-pin fans, and the +VDC supply on Pin #2 is varied by the mobo port. More recently a different fan type has been introduced which is better in some ways, called a PWM fan. It has 4 pins. The first three pins are the same a 3-pin fans with one important exception - the voltage on Pin #2 is always 12 VDC for a PWM fan port. Then the port also sends out on Pin#4 a new signal called the PWM signal. This is called PWM Mode Control. Inside the new fan, a special chip uses that PWM signal to alter the flow of current from the fixed +12 VDC supply through the motor, thus changing its speed.

So, if you plug a 3-pin fan into a true 4-pin fan port operating in PWM Mode, the 3-pin fan gets only a full 12 VDC on Pin #2 at all times. Moreover, it does not receive any PWM signal from a non-existent wire to Pin #4 and it does not have the special chip to use that signal, anyway. So it can only run at full speed. The ONLY way to reduce the speed of a 3-pin fan is to reduce the voltage supplied to it on Pin #2.