We're starting to see problems with the hookswitches on 7910 and 7940
phones.  First occurrence was a couple of weeks ago, now 2 more in the last
week.  Is this a trend, I wonder?  (Phones are about 5 years old.)  Symptoms
are that when the phone is lifted off-hook, the switch only goes off-hook
for a brief instant, then goes back on-hook.  The caller only hears a brief
click followed by a dead line, and the callee gets a bum rap for hanging up
on his callers.  One of my guys suspects the spring in there is weakening.
Is anyone else seeing similar problems?

Mike Armstrong
UF/IFAS CREC
Lake Alfred, FL

[ Post a follow-up to this message ]

http://www.cisco.com/warp/public/78...ook_switch.html

in short,
Introduction 
A thorough analysis of a large number of cisco IP Phones that have been repo
rted as hardware failures has been completed and our research reveals that t
he great majority of these phones do not have any determinable failure. The 
standard by which the phone industry measures phone failures is based on Bel
l Corp/Telcordia standards and the standard acceptable failure rate is set a
t 4 percent. The cisco IP Phone's overall failure rate is well under the acc
eptable industry average. Many of the problems that have been reported as ha
rdware failures are really either operational or cleanup issues. This docume
nt describes some common troubleshoot steps to be taken before you attempt t
o replace the cisco IP Phone.

Self Cleaning Hookswitch Contacts 
The hookswitch contacts design uses a wipe action to self-clean the contacts
. Periods of nonuse of the phone allow air impurities such as dust and other
 contaminants to hinder contact performance, which results in intermittent o
peration. Press and release the hookswitch rapidly a dozen times or so to cl
ean the contacts.

If none of the solutions above remedy the situation, Return Material Authori
zation (RMA) the phone.


----------------------------------------------------------------------------
----
Lelio Fulgenzi, B.A.
Network Analyst (CCS) * university of Guelph * Guelph, Ontario N1G 2W1
(519) 824-4120 x56354 (519) 767-1060 FAX (JNHN)
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 
"I had a coffee and Coke at lunch today...and now, I've got more jitter than
 an
IP phone on a long haul 10base2 connection"                              LFJ
----- Original Message ----- 
From: Mike Armstrong 
To: cisco-voip@puck.nether.net 
Sent: Wednesday, August 31, 2005 4:25 PM
Subject: [cisco-voip] Hookswitch problems on IP phones


We're starting to see problems with the hookswitches on 7910 and 7940 
phones.  First occurrence was a couple of weeks ago, now 2 more in the last 
week.  Is this a trend, I wonder?  (Phones are about 5 years old.)  Symptoms
 
are that when the phone is lifted off-hook, the switch only goes off-hook 
for a brief instant, then goes back on-hook.  The caller only hears a brief 
click followed by a dead line, and the callee gets a bum rap for hanging up 
on his callers.  One of my guys suspects the spring in there is weakening. 
Is anyone else seeing similar problems?

Mike Armstrong
UF/IFAS CREC
Lake Alfred, FL 

 ________________________________________
_______
cisco-voip mailing list
cisco-voip@puck.nether.net
https://puck.nether.net/mailman/listinfo/cisco-voip

[ Post a follow-up to this message ]

> We're starting to see problems with the hookswitches on 7910 and 7940
> phones.  First occurrence was a couple of weeks ago, now 2 more in the las
t
> week.  Is this a trend, I wonder?  (Phones are about 5 years old.)  Sympto
ms
> are that when the phone is lifted off-hook, the switch only goes off-hook
> for a brief instant, then goes back on-hook.  The caller only hears a brie
f
> click followed by a dead line, and the callee gets a bum rap for hanging u
p
> on his callers.  One of my guys suspects the spring in there is weakening.
> Is anyone else seeing similar problems?

Yup.  This is about the only hardware problem on the 7910/7940/7960 that I
know of, but a lot of us run into it eventually, if we're handling a lot
of phones.  I'd guess than 1% of the phones I've dealt with have developed
this problem eventually.

-Bill

[ Post a follow-up to this message ]

The suggested "fix" from cisco has never worked for me.

What has worked, however, is disassembling the 2 pieces of the phone shell
(front & back, should be 4 screws)

On the front half, where all of the electronics are attached, find the
hookswitch and remove it.  Underneath, there is a small white contact pad.
Lift the contact pad and clean the contacts underneath, which are probably
turning a gold-ish color, with an eraser until they are as silver as
possible.



Reassemble everything and you should be good to go.



Hope that helps

-Dave

_____

From: cisco-voip-bounces@puck.nether.net
[mailto:cisco-voip-bounces@puck.nether.net] On Behalf Of Lelio Fulgenzi
Sent: Wednesday, August 31, 2005 4:28 PM
To: cisco-voip@puck.nether.net
Subject: Re: [cisco-voip] Hookswitch problems on IP phones





http://www.cisco.com/warp/public/78...ook_switch.html



in short,


Introduction


A thorough analysis of a large number of cisco IP Phones that have been
reported as hardware failures has been completed and our research reveals
that the great majority of these phones do not have any determinable
failure. The standard by which the phone industry measures phone failures is
based on Bell Corp/Telcordia standards and the standard acceptable failure
rate is set at 4 percent. The cisco IP Phone's overall failure rate is well
under the acceptable industry average. Many of the problems that have been
reported as hardware failures are really either operational or cleanup
issues. This document describes some common troubleshoot steps to be taken
before you attempt to replace the cisco IP Phone.


Self Cleaning Hookswitch Contacts


The hookswitch contacts design uses a wipe action to self-clean the
contacts. Periods of nonuse of the phone allow air impurities such as dust
and other contaminants to hinder contact performance, which results in
intermittent operation. Press and release the hookswitch rapidly a dozen
times or so to clean the contacts.

If none of the solutions above remedy the situation, Return Material
Authorization (RMA) the phone.



----------------------------------------------------------------------------
----
Lelio Fulgenzi, B.A.
Network Analyst (CCS) * university of Guelph * Guelph, Ontario N1G 2W1
(519) 824-4120 x56354 (519) 767-1060 FAX (JNHN)
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
"I had a coffee and Coke at lunch today...and now, I've got more jitter than
an
IP phone on a long haul 10base2 connection"
LFJ

----- Original Message -----

From: Mike <mailto:mfa@crec.ifas.ufl.edu>  Armstrong

To: cisco-voip@puck.nether.net

Sent: Wednesday, August 31, 2005 4:25 PM

Subject: [cisco-voip] Hookswitch problems on IP phones



We're starting to see problems with the hookswitches on 7910 and 7940
phones.  First occurrence was a couple of weeks ago, now 2 more in the last
week.  Is this a trend, I wonder?  (Phones are about 5 years old.)  Symptoms

are that when the phone is lifted off-hook, the switch only goes off-hook
for a brief instant, then goes back on-hook.  The caller only hears a brief
click followed by a dead line, and the callee gets a bum rap for hanging up
on his callers.  One of my guys suspects the spring in there is weakening.
Is anyone else seeing similar problems?

Mike Armstrong
UF/IFAS CREC
Lake Alfred, FL

 ________________________________________
_______
cisco-voip mailing list
cisco-voip@puck.nether.net
https://puck.nether.net/mailman/listinfo/cisco-voip

[ Post a follow-up to this message ]

On Wed, 2005-08-31 at 16:30, Bill Woodcock wrote: 
>
> Yup.  This is about the only hardware problem on the 7910/7940/7960 that I
> know of, but a lot of us run into it eventually, if we're handling a lot
> of phones.  I'd guess than 1% of the phones I've dealt with have developed
> this problem eventually.
>
>                                 -Bill
>

Indeed. We have traced that particular problem to the small carbon disk
used in the off-hook sensor. Replacing this (looks to be about a fifty
cent part) normally brings the phone back to perfect working order.

Probably all the carbon disks used in the button sensors are degrading -
but the hook switch sees the most action so it seems to show up there
first.

If you have some junk phones (lightning, coffee floods, etc) take one
apart and pull the small square latex piece off the back of the off-hook
button. Use this to replace the same piece on the problem phone.

If you look at the small latex square you will see the small carbon disk
glued in the middle of it. It's this disk that needs to be replaced.

Too much information. I know... but its fun to bring these guys back to
life. And profitable - I've saved thousands of dollars by doing some
relatively minor repairs on some of our returned cisco phones (that were
no longer under warranty).

Jon Carnes

[ Post a follow-up to this message ]

I appreciate the information from everyone.  I was naively comparing the
$315 7940 to the Western Electric 500-style phone and expecting similar
mechanical reliability.  I can just see the expression on my boss's face
when I tell him to "Press and release the hookswitch rapidly a dozen times
or so to clean the contacts."

So far, TAC has RMAed all my mechanical failures under my Smartnet contract,
but I've had to argue with them once, and I'm concerned about the increasing
failure rate.  If we're expected to repair them ourselves, it would be a
nice gesture on Cisco's part to make spare parts available.

mike

> Date: Wed, 31 Aug 2005 16:28:20 -0400
> From: "Lelio Fulgenzi" <lelio@uoguelph.ca>
> Subject: Re: [cisco-voip] Hookswitch problems on IP phones
> To: <cisco-voip@puck.nether.net>
> Message-ID: <007a01c5ae6a$873f34c0$30196883@cfs.uoguelph.ca>
> Content-Type: text/plain; charset="iso-8859-1"
>
>
> http://www.cisco.com/warp/public/78...ook_switch.html
>
> in short,
> Introduction
> A thorough analysis of a large number of cisco IP Phones that have been
> reported as hardware failures has been completed and our research reveals
> that the great majority of these phones do not have any determinable
> failure. The standard by which the phone industry measures phone failures
> is based on Bell Corp/Telcordia standards and the standard acceptable
> failure rate is set at 4 percent. The cisco IP Phone's overall failure
> rate is well under the acceptable industry average. Many of the problems
> that have been reported as hardware failures are really either operational
> or cleanup issues. This document describes some common troubleshoot steps
> to be taken before you attempt to replace the cisco IP Phone.
>
> Self Cleaning Hookswitch Contacts
> The hookswitch contacts design uses a wipe action to self-clean the
> contacts. Periods of nonuse of the phone allow air impurities such as dust
> and other contaminants to hinder contact performance, which results in
> intermittent operation. Press and release the hookswitch rapidly a dozen
> times or so to clean the contacts.
>
> If none of the solutions above remedy the situation, Return Material
> Authorization (RMA) the phone.
>
>
> --------------------------------------------------------------------------
------
> Lelio Fulgenzi, B.A.
> Network Analyst (CCS) * university of Guelph * Guelph, Ontario N1G 2W1
> (519) 824-4120 x56354 (519) 767-1060 FAX (JNHN)
>  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> "I had a coffee and Coke at lunch today...and now, I've got more jitter
> than an
> IP phone on a long haul 10base2 connection"
> LFJ
>  ----- Original Message -----
>  From: Mike Armstrong
>  To: cisco-voip@puck.nether.net
>  Sent: Wednesday, August 31, 2005 4:25 PM
>  Subject: [cisco-voip] Hookswitch problems on IP phones
>
>
>  We're starting to see problems with the hookswitches on 7910 and 7940
>  phones.  First occurrence was a couple of weeks ago, now 2 more in the
> last
>  week.  Is this a trend, I wonder?  (Phones are about 5 years old.)
> Symptoms
>  are that when the phone is lifted off-hook, the switch only goes off-hook
>  for a brief instant, then goes back on-hook.  The caller only hears a
> brief
>  click followed by a dead line, and the callee gets a bum rap for hanging
> up
>  on his callers.  One of my guys suspects the spring in there is
> weakening.
>  Is anyone else seeing similar problems?
>
>  Mike Armstrong
>  UF/IFAS CREC
>  Lake Alfred, FL

[ Post a follow-up to this message ]