Volume control knob doesn't increase the volume?

Hello,

It sounds like there is internal resistance issue with the volume knob.
To get this fixed you will have to replace the radio as the issue is likely an electrical issue and you cannot just replace the knob.

Here is a helpful video:

https://youtu.be/NncYSNuaESo

I have attached diagrams for your reference.

Please let me know of any questions.
Thank you.