Switch making a high-pitch whine

[Lerxst99]

I just got a brand new 3com Dual Speed Switch 5 plus through work and plugged it in today in my home office network.

The problem is (as described in the subject), the switch is making a high-pitch whine, so loud and annoying it becomes nearly impossible to work with it sitting right next to me.
I can even hear it in the living room, several meters away and I have no way to put it to make it more quiet or isolate the noise.
After a few hours, it's so annoying it's almost as using your fingernails on a blackboard.
Tried a PSU which I can adjust the voltage on to see if it has any effect, but it wouldn't fit in the power inlet, even though the plug looks almost similar to the plug on the stock PSU (12V) that came with the switch.

So the question is, is this switch supposed to make this sound or do I have a flakey switch? I also noticed that my Inspiron 8100 have to be forced to 10mbit in order to work at all with the switch, otherwise the port light is flashing like crazy. My Inspiron 4150 and workstation works great, this happens in Windows or just when turning the laptop on, works perfectly at 100mbit at work and I tried a different port.
I guess this could indicate that the switch is flakey. By the way, the high-pitch whine is there even with nothing plugged in to it, and I've disconnected every power chord to see if some other equipment is affecting it. To no avail.
- Anyone?

 

[TimRegester]

You have a flaky switch, If bought from new I would return it to the supplier if that is not possibel it should be replaceable by 3Com under the warranty. I would suggest if you phone the supplier/vendor hold the phone to the switch to convince them it is duff.

If you go the 3Com route then I would register it online first.

 

[Lerxst99]

Thanks.
I got a replacement switch yesterday and it makes the same noise.
So either both are parts of a bad batch or these low-end 3com switches are simply noisy.
Either way, it's impossible to use it because of the noise it makes so I have to return them and get another brand.

 

[worker99]

Hi,

open the switch up and you will find two electrolytic capacitors have blown their tops.
Replace with 2200uf 16v.

Problem solved.

 

[TimRegester]

Surely this points to an electrical problem either with the PSU or the electical feed to the PSU. I would investigate the cause and fix the issue there, rather than fix the problem by replacing components, or is there a problem with the switch.

I have the exact same switch and it is as silent as a mouse after my cat has killed it. I do have a belkin surge protecting block but that is just sensible where I live.

 

[Lerxst99]

> I have the exact same switch and it is as silent as a
> mouse after my cat has killed it. I do have a belkin
> surge protecting block but that is just sensible where I
> live.

When I got the replacement switch, I couldn't believe my own ears (literally) since it made the same noise and I did have a hard time believing it could be faulty too.
To be on the safe side I plugged it into an electrical socket at work, to rule out any sudden electrical surge or anything that would kill something in the PSU or something else, but it instantly made the same whine.
I tried with the PSU from an old 3Com Hub-4 as well to rule out any PSU trouble, but it didn't make any difference.

Finally I agreed with the reseller to try another switch, instead of just having a third 3com switch and find out it makes noise too. I got a D-link DES1008D instead, and it's possibly even more silent than a mouse after your cat has done it's job, so now I am quite certain that both switches were definiately at fault.