Blank Screen after factory reset 7911 phone

[STYLIANOS DEMETRIOU]

Hello guys,

I had a weird issue on an 7911 ip phone. It was connected to my network and on the display of the phone was saying "ethernet disconnected".

What i did was a soft and a hard reset using 123456789*0# and then 3497672850*# following the guidelines of a conversation in the forum

https://supportforums.cisco.com/thread/2166581

After the factory reset the device has a blank screen (I left it for more than an hour connected on the network bearing in mind that some processes might be loading in the background and the firmware will load at some point..that didn't happen) and it is unable to receive an ip address ("show ip dhcp bindings", shows nothing related to the mac address of that device).

To eliminate the possibility that the problem might be on the network card of the phone, i've factory reset a working phone using the above described procedure.

I had the same problem with that phone too.

Are there are any log commands that i can use to further investigate my issue?  (I can't see any logs using "terminal monitor"command)

I am using call manager express 4.3.0 on a cisco 2800 router.

[Gordon Ross]

Wireshark is your friend here. It's the only way you'll see what the phones doing.

GTG

Please rate all helpful posts.

[Dragan Ilic]

Please follow the procedure completelly:

http://draganchilly.blogspot.com/2014/02/cisco-ip-phone-recovery-procedure.html

It should help

HTH,
Dragan

[STYLIANOS DEMETRIOU]

Dragan,

I tried what you suggested with no luck.

What i noted is that, when i plug the power adapter on the phone and connect the ethernet cable on the switch port of the phone (the other end goes to a d-link small switch) the light on the small d-link switch doesn't come up. However if i plug the ethernet cable on the pc port of the phone the light goes green. I checked it with two phones that i've factory reset and it is the same problem.

What i understood from this, is that the pc is unable to retrieve an ip from the dhcp server and the necessary option 150 to locate the tftp server and retrieve the necessary firmware.

Gordon, due to the above mentioned problem i can't proceed with wireshark since i don't have network connectivity between the phone and my workstation.

Guys, do you have any alternatives that i can give a try?

Thanks a banch!

[Dragan Ilic]

Did you follow procedure completelly - direct connection between pc and phone? With tftp32 you will have your internal DHCP on PC and you have log so you can see if phone is looking for some address?

If phone is not completelly dead (and I think that yours is not) procedure which I gave to you must work...

HTH,
Dragan

[STYLIANOS DEMETRIOU]

I removed the switch between the phone and the workstation and i connected it via cross over cable (swith port of the phone goes directly to the network card of my pc) but the local area connection shows disconnected.

I am very frustrated since, i've used a second phone that was working properly and i did a factory reset to double check that the problem was not the sw port on the cisco ip phone and now i have two phones that are out of orders.

I still not get it...the pc port on the phone gives signs of life but the sw port is somehow dead or deactivated. (Also the power adapter is connected on the phone and provides power since the phone is directly connected on the pc).

Any ideas?

[Dragan Ilic]

Straight throw cable...

Not crossover - you are connecting PC to internal switch of phone...it must show as connected

HTH,
Dragan

[STYLIANOS DEMETRIOU]

I've enabled straight throw but still the packets can't pass through the cable and wake up the lan card

Please advise anything else to try!

[jorge.zamorano1]

Exelent 

works great and my 7911 come back to live.

regards !!!!

[AldevinoFerreira92137]

i have blank Screen after factory reset 7911 phone ....please help me.