I have an NES that was giving me a blinking red light when powering up. I had chalked this up to the 72-pin connector and set about cleaning it. After cleaning the connector and all games, the problem persisted. I replaced the connector with an aftermarket one, with the same result.

At this point, I assumed it was the 10NES chip, and cut pin 4. Now, when I boot, I just get a blue screen, with either the original 72-pin or the aftermarket.

EDIT: Its most definitely not the TV, I've tried it on two different CRT units, both of which work fine with other older, composite output based consoles.

I have also tried another AC adapter. Like I mentioned originally, it was working, just not reliably.

RF output also produces the same result.

  • What is the purpose of cutting pin 4? Does it completely disable the 10NES check?
    – bjb
    Mar 29, 2017 at 16:48
  • 1
    The chip is known to fail, and even with a licenced cart in the system, can still fail to validate and cause the system to endlessly reboot, which is what the blinking red light is indicating, an endless reboot.
    – DanBig
    Mar 29, 2017 at 17:42
  • Is the red light solid after the 72-pin connector swap? Is the red light ever solid?
    – cbmeeks
    Mar 29, 2017 at 20:10
  • @DanBig were you ever able to figure this out or gain additional info? How dirty is the mainboard?
    – montag
    Aug 16, 2017 at 4:56
  • @montag, I ended up buying another console, this one is still in pieces.
    – DanBig
    Aug 16, 2017 at 11:33

2 Answers 2


Have you tried swapping out the power adapter? Perhaps it's not getting enough power? Do you have another NES that you can swap parts from and eliminate components by trial and error?

Also perhaps your TV can't handle 240p content. There are known issues regarding this; hdretrovision.com has a good blog article on compatible TVs:


  • 2
    Please link to the article that you have mentioned in your answer.
    – wizzwizz4
    Mar 29, 2017 at 20:17

As montag said, it could be your TV (good call on that).

One thing I would try is locating an old CRT TV and try that. Also, if your modern TV has it, try using the Coax (RF) connector. Surprisingly, many modern TV's still have that connector. It might look terrible but it should show if the NES works.

But my first suggestion of an older CRT TV would be the first one.

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