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Hello all,

This is my first post, so, I apologize if it's in the wrong forum, but this looked like the appropriate place for this topic. All my research online can't seem to yield a workable solution for this problem.

This started about four or five days ago. I was playing my front-loading NES, model 001 from 1985 when I discovered horrible looking wavy lines pervading the screen. The actual game graphics were totally fine, but, it looked like there was a problem with the composite cables I was using. The screen basically looked like this:



I always have my NES plugged directly into my 46" Samsung LCD (as I do all my other game consoles). My first instinct was to try a different set of composite cables, but, it didn't solve the problem. Next, I tried it on an old CRT television with the NES RF Switch, but, it had the same issue. I tried it on another LCD, but, same deal.

After doing some searching online, I came to discover a lot of people suggesting it was a problem with the power supply. I always use the official NES AC adapter, but, it was plugged into a power bar, so, I tried plugging it directly into the wall outlet. The problem didn't go away. It was also suggested elsewhere that it's possible there was a problem with the capacitors. Being no expert in soldering and my understanding of how circuit boards and so on work, I figured the next best alternative was to swap out the motherboard from another NES with a non-functional 72-pin connector into the one I was having problems with since the pin connector on the one I always use is totally refurbished. After making the swap and using a different official NES adapter, the problem appeared fixed! The wavy lines were gone and everything was back to normal...

However, two days later, I went to play the NES again, and the wavy lines had returned! How can that be possible? After making the motherboard swap, which included the capacitors, it was basically a completely different NES. The swapped out motherboard was from a later model of the NES, specifically a Mattel Canada variant. The original was from launch in 1985. It seems very strange that two completely different motherboards and setups would decide to experience the exact same problem within a day of each other.

It was suggested on a YouTube video comment section that possibly swapping out the power/reset buttons could solve the problem. However, after I attempted that, it didn't help. The wavy lines were still present.

I'd like to know exactly what causes the issue to crop up, if possible. I've had my NES setup like this, basically unchanged for almost six years. Why would it suddenly happen like this? And, short of going to a top-loading NES, is there any other solution I can try or changes I can make to the environment to possibly remedy this situation? I'm not sure if this is related or not, but, when the problem happened again on the swapped-out motherboard, I tried the RF switch again on the CRT TV and it the sound was making a horrible buzzing noise that didn't happen before. Like I said, I don't know if it's related to this problem or not, but, it might be another clue.

I'm basically out of ideas. Any comments or suggestions would be appreciated.

Thanks!

The really weird thing is that it's not constant from scanline to scanline. The source of interference is somewhere around 1.35MHz or so... That strongly implies the interference is not from inside the NES, because everything inside is running from the same clock.

Did you move your NES physically around the room after those couple days?

No, I put it back where it was originally. By the way, that screencapture is NOT from my NES. It's from a YouTube video that was producing the same problem, however, the results are largely the same.

I see the same thing. Often, moving the video cable around fixes it. Is there an AM radio station on the ~1300 kHz frequency in your area?

Not that I know of... and if there were, it must have just sprung up overnight because I was playing the NES a day before the problem originally started and there was no indication of any wavy lines at all.

However, something environmental would account for the fact that the swapped out motherboard experienced the same problem inside such a short time.

The moving of the cable didn't do anything - like I said, the issue was prevalent with both the composite cables and RF switch connection.

EDIT: New clue: Holding the power button in affected the intensity of the waves... they were much more pronounced with the power button being held in.

That doesn't make any sense ... unless you're acting as an antenna and coupling to the system.

So, I've just tried a THIRD NES toaster and the same issue of wavy lines is appearing on that. So, it's got to either be a problem with the power adapter itself or something environmental. However, the Super NES, Nintendo 64 and Wii I have connected to the same outlet on the same television exhibit no abnormalities.

You guys ever hear of the power adapters themselves becoming defective?

An entirely different NES or just a third set of guts?

An entirely different NES, ungutted.

The NES is unique among that set because it takes 9VAC input, and rectifies and filters that inside, whereas the SNES and later ones use DC supplies (of varying sophistication).

A really simple test would be to use a stack of batteries to make >=7VDC and supply it to the NES (at the normal AC power jack) and see if this interference still appears. I have this hunch that it will, though.

(You could even use a normal 9V battery but it won't last long ... those things are only good for ~5-10m at the kind of power draw the NES has)

Another thing to try is a Sega Genesis model 1 power supply, which produces DC at a voltage that the NES's regulator accepts.

Is a ground loop between the NES Control Deck and the TV possible?

It depends - I'm no electrical genius, but, what would cause a ground loop?

Besides, it seems unlikely as I tried it on a completely different TV in a completely different room on a completely different outlet with the same result.

EDIT: Some new information - originally, I was only using a copy of Super Mario Bros. to test the screen, which produced the wavy lines. I then put in Dr. Mario and they were GONE - totally. I switched over to Metroid and again, gone. I put SMB back in and back, though diminished. I thought maybe it had something to do with the darker color schemes of Dr. Mario and Metroid affecting it, but, I also tried The Legend of Zelda, Family Feud and NES Open Tournament Golf and they were mostly clear. There were some waves on the title screens of Zelda and Golf, but, they dimished after about 10 seconds. Then, the strangest bit yet, I tried the Super Mario Bros./Duck Hunt cartridge and got no waves on the SMB title screen, switched back to just the SMB cart and had diminished ones!

What in the heck is happening here?

Bad caps in the PSU/Mobo is all.

But he tried 3 different NESes and they all exhibited the behavior.

It could very well be your TV, or interference from something near your TV. If not the power adaptor, that is.

Well, now I've tried a Sega Genesis adapter, and the waves were still there.

I really don't understand this. They seem to vary in intensity, sometimes they're very pronounced, sometimes they're hardly visible at all. There's just no rhyme or reason, that I can see. I even went so far as to unplug all my electronics and re-set them up, making sure they were all straight cables and no effect.

The last thing I can try to is to take the NES to another place entirely and see if it affects any difference.

As Drag suggested, if it were something near my TV, you'd think the problem would have eliminated when I moved the NES to another room entirely, but, it didn't... and I haven't added any new electronics to my set-up in quite a long time, so, I don't know what could be causing it. I'll report back after I've tried it at a friend's house, which is in the next town over.