Volume level jumps uncontrolled

Hi everybody,

i’m running Volumio 2.02 on a Raspberry Pi A+.
When i try to control the volume level of the playing music the level jumps uncontrolable between 40 and 100. I thought maybe the performance of the Pi could be too bad and tried to overclock the system.
I used a guide from this forum and got to the point where i need another password to get access to the raspi-config file. When i use volumio as password it replies “command not found” whereas on every other attempt i get “sorry, try again”. Do you know what i have to use?

Thanks for your help,
Apotab
Example.jpg

Anyone?