Cisco C20 making strange noises

[teckardt2012]

Hello,

I have the following problem: in our company we have a C20 from a costumer and the machine makes strange noises. It sounds like statics noises. I've uploaded a video in wich you can hear the sound. It doesn't matter what we connect as sound output, the noise will stay. The most strange thing about the noise is that their seems no pattern behind triggering it.

For example, I started the codec and their was no noise. So I decided to make a test call, I noticed that the ethernet-cable was unplugged, I plugged it in and their was the noise again. So I restarted te codec, with the ethernet-cable plugged in and as soon the codec had booted and showed the main menu you could hear the noise. I pull the ethnet-cable out, restarted and no noise. Plugged the cabel back in, no noise. I looked in to the Phonebook and the noise started again.

For now, I was unable to find a method to always reproduce the error. The appering of the noise seems to be absolutely random.

So if you have a idea or need additional information, please let me know.

[mubakhta]

Hi Tobias,

Can you tell us what kind of noise is this? Does this look like a fan noise to you ?? Or is it something which is static in nature and can be caused by other equipment within the same room ? Can you try and shift this endpoint to another location and then check if the noise is still there? In all previous instances of noise, we have seen either its a fan noise or noise due to other equipments in the environment.

Regards,

Mubashshir Akhtar

[teckardt2012]

Hi Mubashshir,

thanks for the fast response. It's definitely no fan noise. Because fan noises would come from the codec itself but the noise comes from what ever device used for sound output. In the video we had speaker connected with the codec and the noise comes out of the speaker. We also had a TV plugged in and the noise came from the TV.

It's also very unlikely that the equipment in the surroundings has something to do with it, because the costumer, from wich we have the codec, has the same problem. And he has a completely diffrent surrounding than we have.

What I don't get is the random nature of the error. Right now the codec makes the noise again, but this time the frequency is much slower. It sounds more like a knocking, than it speeds up till it sounds like in the video if uploaded in the first post, than it vanishes. Only to start all over again. This behavior is new, it never done this before. It seems like the more I'm trying to figure out what happens, the more random it gets.

Regards,

Tobias Eckardt

[mubakhta]

I see. In that case, can you tell us which ports are you using to connect the audio output? As you mentioned TV as well as speakers, I assume that you must be using HDMI as well as RCA ??? That means you're either using the TV speakers or attaching external speakers. Please confirm.

Regards,

Mubashshir Akhtar

[teckardt2012]

Yes we used HDMI for the TV and the speaker we connected over RCA. But it doesn't matter wich one is used, the problem remains, even if only RCA or HDMI is connected to the codec.

Just to keep you up to date what we have tried so far: a co-worker of mine gave me the tip to change the PSU. So I did and it changed nothing. But I only had a PSU with 12V - 4,1A nearly the same as the one we had connected before (12V - 4A). Could it be that the PSU is to weak? Could that cause a problem like that?

Regards,

Tobias Eckardt

[mubakhta]

Hi Tobias,

Have you tried using spare HDMI & RCA cables ? Also I would request you to try and do a factory reset to make sure that it is not a configuration related issue. Although this looks like a hardware failure. We're doing the factory reset just to be sure.

Regards,

Mubashshir Akhtar

[teckardt2012]

Hi Mubashshir,

yes we have tried diffrent cables with no result. So I followed your advice and reseted the system but as you were expecting, it changed nothing.

Regards,

Tobias Eckardt

[mubakhta]

Right Tobias,

as we suspected. This seems like a hardware failure. Please go ahead and open a TAC case and we will process the replacement.

Regards,

Mubashshir Akhtar