Whiny Motherboards

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BB Gun

[H]ard|Gawd
Joined
Jan 14, 2004
Messages
1,551
OK, I'm noticing this more and more. First in a cheap MSI K8MMV board that I ended up giving away, in an unnamed board in a friends system, and now in the board in my sig.

I added the WD drive the other day, and my motherboard now emits a faint, high pitched irregular whine. Sounds like the whine of a CRT - barely audible, but just enough to bother you.

Is it just cheap power mosfets causing it?

Is there any way to stop it?

My system didn't have the whine before I added the drive - and no, its not the drive whining - nor the PSU. Its coming from something in the power mosfet area between the CPU and backplane of the motherboard.

BB
 
If it was from adding another peripheral, its likely not the motherboard, but the PSU. I know you state that its not the case, however, adding load on the PSU (not the motherboard) shouldnt affect the MOSFETS on the board.

If you had added another PCI/PCIe device, then sure, but a hard drive... I think not.

Try changing it out, and see what it does for you.
 
your sig has a Antec Smartpower 2.0 550W. Get rid of it before it gets rid of your PC.
 
upriverpaddler said:
WHAT?!?!
Click to expand...

The whine usually originates from the back of the PSU, it seems like it's the motherboard, it very well could be, but if you drop in the Power Supply subforum you'll see what I'm talking about when it comes to Antec SPII's :)
 
It might be a capacitor problem with the motherboard. Check those first. Also try to isolate the power supply and test to see if the whine is coming from there too.
 
Actually, I revise my statement earlier, the noise may in fact be coming from the mosfets, but I would say that would be from dirty power coming from the PSU due to the increased load on it.

I didnt even notice the Smartpower 2.0 in your sig, yea.. I would absolutely change that out.
 
AKA as "Capacitor Squeal or excessive loading. You're pushing the 'board too far. When you back off the O/C the noise goes away.

MICROPHONICS

Semiconductors are not prone to microphonics themselves, but some other circuit elements can cause them. One case is the inductor used in some LC oscillators, particularly in the radio-frequency range. This effect can sometimes be minimized by firmly anchoring each turn of the coil with special adhesives such as RTV. Phase-locked loop cuits can be sensitive to microphonics generated by the physical movement of the inductor used in the oscillator.

Capacitor Failure Patterns in DC Circuits
The majority of capacitor failures, perhaps 90%, involve the internal shorting of the capacitor. Once shorted, the capacitor frequently causes power-supply overload, often causing the power supply to blow a fuse or other wise fail. In less drastic failures, the capaitor no longer functions to isolate DC voltages from one circuit to another. If power is still applied, this failure is easilly determined with a DC voltmeter since there is a zero voltage drop across a shorted coupling capacitor.

...If the electrolytics are bad, the oscillation can be a squeal...


James Perozzo: Practical Electronics - Troubleshooting

http://repairfaq.ece.drexel.edu/sam...irfaq.ece.drexel.edu/sam/smpsfaq.htm#smpsstsm


Sounds that SMPSs make
Most switchmode power supplies when operating normally produce little or no detectable sound. The switching frequencies are usually well above the range of human hearing, but your dog or pet dolphin might be driven nuts!

However, under various fault conditions, and sometimes when lightly loaded, there may be tell-tail audible indications of the SMPS's state of happiness. The cause may be in the SMPS itself or its load.

1. Tweet-tweet-tweet or chirp-chirp-chirp (sometimes flub-flub-flub) - Short circuit or current overload. This is usually an indication of a shorted secondary-side rectifier and/or if in a TV or monitor using an SMPS, a shorted horizontal output transistor. The power supply is in a repeating cycle attempting to start up, being dragged down by the overload, and shutting down.

2. High pitched, but audible, whine - Excessive load. Like (1), this may be caused by shorted components. For example, a common failure a Panasonic VCR power supply is for the 18 V zener diode across the 15 V output to short due to dried up electrolytic capacitors. The result in an overload and whine.
 
lol.. where'd you get my quote...

and for the most part Antec uses crap caps in the secondary...

My true430 is dead because of this...
 
Thanks for the info, qdemn7.

But...
qdemn7 said:
AKA as "Capacitor Squeal or excessive loading. You're pushing the 'board too far. When you back off the O/C the noise goes away.
Click to expand...
I'm not overclocking. :(

BB
 
You can get it even with no overclocking...

Another source is the torroids, or coils, on the board, this is fixed by potting the coils with RTV silicone.
 
Potting = gooping it up, taking care not to insulate the mosfets by getting RTV silicon on them as well?

Thanks,

BB
 
Why not start doing some basic troubleshooting first? Determine if it's the motherboard or PSU or whatever before you start throwing your goop around :p
 
Was planning on it, I was multitasking. :p

That being said, I shut my system down, and whattaya know, the sound's coming from the PSU, not the Mobo.

I turn off the PSU switch, the whine goes away. Turn it back on, and the whine is back.

:(

Time for a new PSU, I reckon.

BB
 
BB Gun said:
Was planning on it, I was multitasking. :p

That being said, I shut my system down, and whattaya know, the sound's coming from the PSU, not the Mobo.

I turn off the PSU switch, the whine goes away. Turn it back on, and the whine is back.

:(

Time for a new PSU, I reckon.

BB
Click to expand...

Antec has a 3 yr warranty on their PSU's. If you still fall under that, make sure to let them know to replace it with a Trio or something, just stay way from the Smart Power line.
 
Exactly, raise hell and get it replaced by Antec, also if you bought it with a Visa card, Visa will sometimes give you an extra year on the warranty..
 
Unfortunately, I've got no receipt. This was one of those few times I bought something from Fry's on special, so I have no Newegg invoice to fall back on. :mad:

I'll still contact them to see if I can whine my way into a replacement, but given that I've got no receipt, they don't have to honor their warranty.

Just in case it went out, I got an FSP AX450-PN PSU from the Egg. Its been sitting around for a week - until tonight. Turn on my system, and now in addition to the capacitor whine, I get a horrible grinding noise from failing fan bearings. I rip it out, put in the FSP and... ahhhh, back to peace and quiet.

BB <--- off to complain to Antec.
 
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