Nintendo 64 Image loses sync and garbles audio after a certain period of playing

[dotmatrixmoe]

Just as the title suggests, the output of my Nintendo 64 after a certain period of time (often an hour) starts with crunchy audio, and then the image appears to lose sync. I thought at first that it must've been my RGB cable, but it appears to have the same effect with my composite cables. My console is an NTSC region NS1 serial console, with Voultar's RGB amp installed by me.

I have two possible scenarios:

• The composite signal of my console is being sync cleaned in the SCART cable, explaining why the composite cables also garble up; the composite signal is the issue.
• My console needs a recapping due to age.
  
  Any help would be appreciated.