Old radio tuner string fix

This video is general instruction how to install tuner string / cord of an old radio device. Problem is that tuning knob is not doing anything, because tuner string is old, worn and hardened. I will explain how to diagnose the problem, how string operated tuner should work and how to fix it.
NOTE: Suitable string can be found in hardware stores, I like to use nylon-string which is found in fishing-category. Just choose about same thickness and you're good to go.
Device I'm working on is JVC, but many older radios have similar type of working principle and basic components.
Side note:
I'm a mechanical engineer, but what it comes to electronics, I'm mostly self-learned. Do not try to fix your electronic devices if you're not sure what you're doing. If you handle electrical devices carelessly, you may get electrical shock or cause malfunction to the device.