MSI K8N Neo V2.0 high pitch hiss

[lordshade]

I have an somewhat old mobo MSI K8N neo V2.0 and was using a sata 2 hdd, even though the mobo has sata 1.
Everytime the HDD seeks at high speeds using read/write cache, I hear a somewhat intermittent high pitch hiss(frecvency related i guess) comming from the caps or mosfets or microcontrolers around the sata slot. I can't seem to find the exact location because of the tight space.
Untill now about 2 caps marked KZG 6.3v 1500uF went bad and i had to replace them. The mobo boots up and I can even overclock the processor/ram and it's perfectly stable...but because of that hissing I guess that something else is broken or almost broken around there.
Also the hdd doesn't have the required performance it feels sluggish for example when I'm download something at 5-8mb/s.
And the CPU voltage varries too much...using 1.65v in bios, the mobo sensor shows it at 1.63v and drops every few seconds to 1.60v and rarely to 1.59v.This dropout stays the same when the CPU is idle or in full load.

The power supply is checked and double checked and also it's 1y old, has 500W, voltage is within the 5% limit even in full load, so no issues here.

Is there any chance that one of the mosfets could be damaged ? or the only thing needed is recaping?
I have visualy checked the other capacitors and they seem ok, I didn't want do solder/desolder them too may times because of the increased risk of board damage.

The mobo has some KZE 25v 850uF caps, and I can't seem to find the exact match. Would be ok if i replace them with 25v 1000uF ?

[Th3_uN1Qu3]

Re: MSI K8N Neo V2.0 high pitch hiss

KZEs are good. What you're hearing there is coil noise and it's mostly normal. As for HDD performance, if you're using a torrent client, you need to tweak the disk cache settings.

[lordshade]

Re: MSI K8N Neo V2.0 high pitch hiss

Also there is another issue I forget to mention: if the mobo is shut down but remains plugged in to power, there is a strange voltage commin from one mosfet just above the agp port, and from the usb and many more locations on the left of the CPU.

I think it's on the 5v rail, but is quite lower than 5v...like ~4v Also when the board was new, at shutdown the keyboard and mouse were completly shut off.

Now after I turn it off the keyboard remains active(I can play with num lock/caps lock/scroll lock leds) and there is a dim light in my mouse...one of the leds lights up(the one that shows current DPI) but like 1/3 of normal light intensity, and that's a sign it isn't powered up propperly.
If the mobo is turned on the voltage on that line goes up to 5v and remains there.

[c_hegge]

Re: MSI K8N Neo V2.0 high pitch hiss

Have you replaced -all- of the KZG caps? They are known for going bad without showing it. That could explain the noise, as more of the ripple is having to be filtered by the coils. What brand and series of capacito dis you use to replace the bad ones?

The voltage on the USB when powered off could be because the motherboard is set to use the 5vsb rail to power them.

Also, what brand and model is your PSU? Is it a good 500W, or a cheap no-name 500W (ie. a 200W with a 500W Sticker)

[lordshade]

Re: MSI K8N Neo V2.0 high pitch hiss

No I didn't replaced all the KZG, just the two that went bad with some ChemiCon LXJ i think(I can't see the label completly) 10v 1500uF. I didn't know their reputation at the time.
The noise was there even long before i replaced the damaged caps but had a much lower intensity back then. Also when the mobo was new there wasn't any noise comming from it.

PSU is inter-tech sl-500A..not a very renowned brand but the voltages are quite stable even under load.
5V rail mentains a stable voltage of 4.90-4.91 no matter what i do
12v keeps steady at 11.86-11.90v
3.3v when idle is at 3.30v sharp...and in full load drops at about 3.26-3.28v

Also i have around here some unused LXZ 6.3v 1500uf...they are good for something like this or i must find a more exact replacement?

[c_hegge]

Re: MSI K8N Neo V2.0 high pitch hiss

No I didn't replaced all the KZG, just the two that went bad

There's one problem. The KZGs all have to go. they are notorious for failing without bulging

with some ChemiCon LXJ i think(I can't see the label completly) 10v 1500uF.

There's another problem. LXJ aren't even close to being low enough ESR for this application. Use Nichicon HM or HN, or Rubycon MBZ or MCZ.

The noise was there even long before i replaced the damaged caps but had a much lower intensity back then. Also when the mobo was new there wasn't any noise comming from it.

You may have made the ripple going through the coild worse by using the wrong caps.

PSU is inter-tech sl-500A

That could be another problem. The voltages looking good on the DMM doesn't mean much. you could have stable voltages with high ripple. The SL prefix on the model suggests it's a Solytech/Deer, which can make some horrible PSUs. Could you post a picture of its internals?

Also i have around here some unused LXZ 6.3v 1500uf...they are good for something like this or i must find a more exact replacement?

Those aren't suitable for use on a board. Use one of the series I suggested before (Nich HM or HN, or Ruby MBZ or MCZ)

[lordshade]

Re: MSI K8N Neo V2.0 high pitch hiss

Unfortunately I can't post pictures of my psu's inside because it's still in warranty, and second: I dont have anything that I can take pictures with.

However the issue may be from previous psu...which was indeed a no-name and was used untill the 10v 1000uF caps inside started to bulge(about 2y or so). Maybe that shitty psu damaged something on the motherboard.

That being said, next week I will go shopping for caps...I hope to find the ones I need.
Any advice on how to spot counterfeited caps ?

[c_hegge]

Re: MSI K8N Neo V2.0 high pitch hiss

Yes, don't use fleabay (except for one seller - egekecu). Get them from here and you won't have any problems with fakes. These (https://www.badcaps.net/store/produc...roducts_id=136) should do fine in place of the 1500uF caps. There may be other good suppliers too, depending on what country you're from.

If your previous PSU had bad caps, then all it will probably have damaged is the motherboard's caps.

[lordshade]

Re: MSI K8N Neo V2.0 high pitch hiss

Thanks alot for all the help.