Loud Hum on T46 Handsets

[natesecd]

We have been frequently needing to replace the handsets on the T46 phones because of a loud hum that has crept up. This was with our first batch of phones that we initially installed back in November of 2013. Was there a known bad batch of phones during that time?

Im curious because since then we have deployed many more and am hoping this going to be a common problem.

We have also had this issues with some T28's as well.

I look forward to hearing feedback thank you.

[Elaine_Yealink]

Dear,

As far as I know, we don't have such accident. May I know more about the loud hum issue:
1. Is it happens on call or just list the handset?
2. If replaced with a new handset, will the hum gone?
3. Have you tried to upgrade the firmware to the latest?

Regards
Elaine

[natesecd]

(06-12-2015 02:46 AM)Yealink_Elaine Wrote:  Dear,

As far as I know, we don't have such accident. May I know more about the loud hum issue:
1. Is it happens on call or just list the handset? As soon as the handset is picked up.
2. If replaced with a new handset, will the hum gone? Yes if replace with another handset the hum goes away.
3. Have you tried to upgrade the firmware to the latest? Yes the firmware was the latest

Regards
Elaine

[Frank Drews]

(06-12-2015 02:46 AM)Yealink_Elaine Wrote:  Dear,

As far as I know, we don't have such accident. May I know more about the loud hum issue:
1. Is it happens on call or just list the handset?
2. If replaced with a new handset, will the hum gone?
3. Have you tried to upgrade the firmware to the latest?

Regards
Elaine

1. Even, if no call is etstablished, and the phone is just making the "line ready" sound. During calls, too. But there seems to be no hum, if there is no sound at all, but I am not 100% sure about it.
2. Yes, with a new handset the hum goes away
3. At the moment we are using V73. Upgrading to V73 didn't change things

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(06-12-2015 01:57 AM)natesecd Wrote:  We have been frequently needing to replace the handsets on the T46 phones because of a loud hum that has crept up. This was with our first batch of phones that we initially installed back in November of 2013. Was there a known bad batch of phones during that time?

We are having the same issue. We purchased our phones in November/December 2013.
We had issues with 20 handsets out of 200 active phones since. Sometimes replacing the cable or adding an non-twister adapter would fix the issue, 7 times we replaces the handset. The non-twister adapter are a little wider than the cable plugs and so they don't wiggle. We aquired two different batches, but we didn't collect any data on which phones were affected. And people here don't use their telephone very much, we have no call centre or sales department.

We disassembled the handsets and there seems to be an issue, that the female plug to insert to cable is to wide. The plug has lots of free space to wiggle. I am not an expert on plugs at all, it's more a guess, that this is the root cause for our issues.
Youtube Video showing wiggeling (non-listed)

We are thinking about glueing the plug to the handsets.

The thing is, that people often try different things and suffer bad sound quality for month, before they reach us. So we want to provide a proactive solution.

Any similar experiences?

Best regards Frank

[Frank Drews]

Hi,

I did some more detailed inspection of a handset which had the hum symptom.

One of the 4 spring-loaded contact pins inside the grey plug of the handset was bend and not in line with the others.
After manipulating and re-straightening this pin, the hum did go away.

If a pin is bend or twisted, you can wiggle the plug of the cable inside the grey female plug in the handset all the way you like, it won't change the hum. This may result in the false conclusion, that the plug contact is not the issue, but I can confirm 100% that it is.

I think the contact pin may get bend, because the plug is wiggeling a lot.

We will now start using hot melt glue to fix things.

Best regards Frank