Famiclone screen rhythmically flickers and more

[jdolinski]

Hello from Czech Republic,
so it arrived today,

 

i love the design, whole construction feels solid. Joypads, compared to my halfbroken from past, are nice with good cable length.
See the pics:


Bad luck it has two problems:
- Video:
The screen is fine, the colors are warm, i like it. But after like 3 minutes of playing, it all start flickering, the screen goes grey and... see the video: https://youtu.be/gRmY6Z7aC88
Bad capacitor? Anyone got idea what may be the problem?

- Audio:
Quite ordinary problem with famiclones i think,
weird square tones, out of tune, low/high volumes, etc.
See the video: https://youtu.be/7KdjAaZcdkk
I remember seeing guides where guy soldered resistor on audio output or so to fix it, however, i couldnt find any exact info today.

Any tips?