SNES modded to 60 Hz fickers between 50 and 60 Hz

Hi all. This is my first post, so please forgive me for any mistake I may commit.

I have a PAL SNES that was modded to 60 Hz and no lockout chip around 10 years ago.

It developed a strange issue. I start a game at 60 Hz and after around 20 to 30 minutes the image starts flickering, switching back and forth from 60 to 50 Hz until it completely settles at 50 Hz. After that, if I switch from 60 to 50 and to 60 Hz again the consoles continues to output 50 Hz, like if I had no mod switch at all. I have to wait a few hours (next day) for it to output 60 Hz again and the issue starts again after 20 or 30 minutes.

The switches are working ok and I reviewed the solder joints on the switches and PPUs. Everything seemed ok but I resoldered the PPU mod wires again just in case. The issue continues.

Does someone have any idea of what's happening to my beloved SNES? I'm teaching my daughter to like Nintendo games, my SNES can't die on me now! Maybe it's just old age and there's nothing I can do?

Thanks in advance for any help!

 

Sorry for the bump, but does anybody know what's happening to my SNES?

 

Where do you take 5v from? Try to take it directly from the regulator and see if that makes a difference