SNES random black screen.

SOURCE: Nintendo DS Lite shuts off randomly.

I'm a certified electronic technician and I must say NDS internal screen ribbon connectors are junk! Basically The ribbon connectors are so sketchy that it is not recommended to ever unclip them, if you do there's a good chance it will ever work again once reconnected due to how the connector pins slightly crimp into the ribbon pads.

When a NDS boots up the the onboard firmware constantly tests the LCD screen connections, if there is a break in the connection the NDS will shut down. If your NDS randomly turns off, fails to boot, or powers of when you move the hinge it is most likely the ribbon (flex film) or ribbon connector has failed. The only option to to replace the affected LCD screen.

SOURCE: black dots during gameplay only on 360

in mass effect its an option thing called film grain if that is ur problem u could tern it off from the settings

SOURCE: SNES Sound but no Picture

either the wires could be shot or to an nes the same wires work but sometimes cause errors

SOURCE: Blackberry storm has random resets

Remove suspicious apps one by one. If the problem remains after removing all apps restore the firmware to factory using the desktop manager. If the problem still remains there may be a hardware issue. If you're out of warranty there are Blackberry Repair Guides if you want to attempt a DIY repair, logic boards are on ebay.

SOURCE: Black Screen

It might be your AV cable or the connector for the cable. Try it on another TV just to make sure its the SNES though.