Snes going black screen

Hi,
i have this pal snes (i think a rgb 01 or 02) that, when turned on after a long time, displays the game for like a couple of minutes, then goes black. If i reset or turn off and on again the screen stays black. I have to wait hours before it displays again something for some minutes.
Looking inside everything seems right and clean... what could it be?
thanks

 

The RGB cable, if you use one.

 

I tried two different... is it possible that a cable does this? :O i mean, never heard of a cable that needs hours before showing something again for some minutes then stops again.

 

I had exactly the same problem a long time ago. For me, it was a thermal problem. I changed the 7805 and this solved my problem. You may also try to use thermal grease between 7805 and the heat sink in advance... Try it, but it could also be something different.

 

i checked that chip, like if it was hot... it's not.
Today the snes doesn't even launch the game... just black screen. If i use tototek flashcart there is a blue flash then black, if this can help.

 

Could be the regulator as previous poster pointed. If I was you I would check 5v rail voltage with a multimeter during operation.

 

I had a snes mini that gave me a black screen,I check the 7805 and for the 5v it gave out 7v.

I change it with a working one and it works fine now.

 

Before you try replacing any chips, try a regular AV cable. The barely visible video is a known RGB cable issue on some configurations.

 

i use a snes test cart on a few faulty unit's and can tell me the problem sometimes.