IP Phone:Receiver won't work for some of the phones

[krishnamurthy.mh]

Hi,

We are running CCM 4.1(3).

We are facing problem on some of the IP Phones(7940), like receiver of these phones are not working.You can only able to hear the voice from Speaker mode.

While ringing if receiver goes off-hook, still the rings are continued untill we press speaker phone to pick up the call.

I feel there is no off-hook signal for the receiver...

Any suggestions to resolve this problem...

Regards,

[harris.h]

Is this on your lan or wan?

[AJAZ NAWAZ]

krishnamurthy

Under the device > phone configuration settings page, scroll down to Product Specific Configuration. What do you have set here?

Ajaz

[Rob Huffman]

Hi Krishnamurthy ,

I'm 99% sure its RMA time for these 7940's.This is most likely a problem with the Hookswitch. After deploying Cisco IP Phones for the last few years we (and many others) have found this to be the most common hardware problem. There is a "Best Practice" for cleaning the Hookswitch contacts (link below) that does work on occasion. Usually the phone has to be replaced/RMA'd.

Best?? Practices for Cleaning and Troubleshooting Cisco IP Phone Hookswitch

From this interesting Tech note;

http://www.cisco.com/en/US/products/hw/phones/ps379/products_tech_note09186a00801c0810.shtml

There was also a problem with the 7.2 phone firmware that caused similar looking symptoms but I am pretty sure that it was for the 3rd generation phones 7970/7961/7941. This could be rectified in the short term by booting the phone.

Hope this helps!

Rob

[Datamaster Col]

While this is a late reply I hope it will help others who are having the same issue with the 7800 range and maybe others too.

The issue is a very badly designed receiver, 
there are is another 'hook' inside the phone, that the external hook presses, this is held on to the receiver PCB by 4 very soft and flimsy catches, a simple bit of pressure on these and the hook will pop off or move away from the PCB. so I will assume that normal usage over time and or vibrations will loosen this.

So to fix this issue you need to remove the casing, (Remember there are 4 screws behind the screen faceplate and one or two behind the silver stand)
Then remove the 2 small screws on the receiver PCB.
Now pop out the hook fully, (press the clips in and down) starting with the top two, then the bottom two, be careful with the hook as it is also soldered on to the PCB, but you will have enough play to allow it to move forward, then re seat the hook. (Push it back in)
At this point it would be best to use something to make sure the hook doesn't come away from the PCB in the future, I would suggest a spot of superglue on all four clips or what some of us old school like to use, nail varnish

I would only advice the about fix if your phone is out of warranty, but I have a 100% success rate when getting a phone back with this issue.

I have had to do this to almost half of the phones we've ship out to our clients, in excess of 50+ and probably going to get many more over time.
We have till recently always used Cisco phones for our clients and must have sold thousands over the years, but we have now stopped using Cisco due to this issue and the fact that we had to bin a large number of these that were out of warranty before I found what the true issue was, as speaking to Cisco themselves they are making out its contact corrosion lol.
So for a baldly designed receiver hook, probably to try and save a few pennies in manufacturing has in fact cost our clients a lot of money to replace out of warranty phones with new one that really shouldn't have been needed.