Blank screen and no console access on Cisco switch

hyortiz01 · ‎08-28-2016

Hello:

I saw that some people have this problem. I have no access to the console to my cisco 3560 switch. I can not access rommon mode too. I just have blank screen despite the fact that the serial configuration was done properly:

Bits per second:9600

Data bits:8

Parity:None

Stop bits:1

flow control:None

I just checked the cable and it is ok.

I can also mention that the mode bottom seems that is not working. Is there any suggestion to fix this issue?. Maybe in a hardware level, do i have to change some component?

thanks a lot

johnd2310 · ‎08-28-2016

Hi,

Was this switch working before? Does the switch work when you boot normally i.e. is it just console access that is not working? What happens when you try to boot the switch in rom mode? What LEDs are flashing?

Thanks

John

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hyortiz01 · ‎09-05-2016

Hello John:

First of all, thanks for your response. Now, answering your questions:

1.-Yes, this switch was working before

2.-No , the switch is not working, despite de the fact that I had console access before.

3.-This issue appeared when I tried to recover the IOS through Xmodem process (because I lost the IOS file and the switch only worked in rommon mode)

4.- Now, I can not enter rommom mode, because the switch is blank, It appears that rommon mode is not working.

5.-The only led working is SYST

Georg Pauwen · ‎09-05-2016

Hello,

you could try the following:

1. Connect the console cable. (Make sure the console cable is fine)
2. Unplug the power cord.
3. Press and hold the mode bottom. (you should see all LEDs light up and steady for couple of seconds and then start blinking)
4. Plug the power cord back into the switch.
5. Check if you get something in the console...

Milosz Jablonski · ‎05-08-2018

Hi have the same issue, but have confirmed that

all settings for console session are correct

switch was working before (taken from production environment for wiping before disposal)

console cable works (just worked on another switch)

all leds are coming on on switch boot

can't break into romon and screen remains blank

any help much appreciated....

thanks

Georg Pauwen · ‎05-08-2018

Hello,

which terminal emulator are you using ? If you are not using Putty yet, try that...

https://www.putty.org/

Milosz Jablonski · ‎05-08-2018

yes that's the only emulator i am using

dineshkannan32034311 · ‎02-26-2021

Because you are using terminal mode you want to run command in command prompt

paul driver · ‎02-27-2021

Hello

Try resetting the switch by power cycling it and then press the mode button on the front panel for 15-20 seconds as you power the switch back on.

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Paul

Aijaz Rehman · ‎05-19-2024

I can understand you might have tried lot of options but still you are stuck on blank screen on console, just cursor is blinking

I had same issue with Cisco Catalyst 3550, I did Power ON/OF several time by removing power cable behind switch and kept console active and i got the prompt but if you don't try this silly method do go through below:

please check if your switch is having only SYST light on and nothing else is blinking that means your switch is not dead yet, it can be back to its life, go through this video:

https://www.youtube.com/watch?v=FpeZEswrH-s

after doing that process if you got Prompt switchname# directly well and good if not, you might get prompt SWITCH: by pressing mode button, then do the below steps:

Step 1.

Connect up your console cable and power on the switch, whilst holding down the “mode” button:

Step 2.

Initialize the flash file system with the command: flash_init

Step 3.

Delete the config.text file from the flash directory:

switch: del flash:config.text

Are you sure you want to delete "flash:config.text" (y/n)?y

File "flash:config.text" deleted

Step 4.

Delete the vlan.dat file from the flash directory:

switch: del flash:vlan.dat

Are you sure you want to delete "vlan.dat" (y/n)?y

File "flash:vlan.dat" deleted

Step 5.

Reboot the switch and you’re done:

switch: boot

-----------------------------------------OR---------------------------------------------------------

switch: flash_init

switch: load_helper

switch: Dir Flash:

switch: rename flash:config.text flash:config.old

switch: boot

------------------------------------------OR-------------------------------------------------------

if switch didn't boot properly, then you need to reset the switch but you will loose all the DATA, to proceed follow below