I have a snes that displays snowy/wavy dotted lines on the screen for all games when using composite cables. it is mostly visible on dark colors. the display is clear when using the rf adapter. I have tried different cables and they did not fix this. I opened the console and took all parts off that are held with screws. I cleaned everything visible with rubbing alcohol. I cleaned the cartridge slot with a card and coffee filter. I don't seet any broken solder or loose parts. anyone know how to diagnose the problem?

Hmm. I'd wager you have a component failure somewhere in the console if changing the cables didn't help. I'm curious if it shows up on s-video and RGB outputs as well. The RF modulator might be blurring out the noise on the signal, causing you not to see it through there.

I doubt that is a loose connection or broken solder joint. Something has worn out and needs replaced. It's impossible to tell for sure without examining it. A Multimeter, and an Oscilloscope will probably be needed to troubleshoot it properly.

How long have you had the console? If awhile, has this started happening recently, or is it a long-term problem?

I'd be willing to look at it if you'd like, but my return time is 2-4 weeks+ right now due to my college schedule.

I bought the console a few months ago, it has been like this since I first used it. I have a multimeter and access to an oscilloscope.

I will have to order a s video cable to test that. I don't have a display that will do rgb unless I use a hdmi converter, which I also don't have but can order one.

should my next step be trying s video and rgb?

are there any resources you know of I can use to diagnose the failed component?

thanks

What AC adapter are you using? Is it a stock adapter, or a cheapo third party one? If the latter, that might be the culprit. The commercially available third party adapters on the market specially made for old consoles are almost all garbage that will damage your console due to not supplying enough current.

The next step I'd take is visually examining the electrolytic capacitors on the board. Those are generally the most common failure point for 20-30 year old+ electronics. Look for any signs of leakage, corrosion, or buldging. You might have washed some of this away by cleaning it first, so if it is there it might be hiding. If I recall some models of the SNES use SMD electrolytic capacitors.

Don't spend money on cables unless you want to upgrade to s-video.

As far as resources for troubleshooting, I suggest you find out what board revision you have and give this page a thorough look over: https://console5.com/wiki/SNES...

HQ board pics would help. Give some close ups of the caps in the A/V area, and power supply area if you can.

I am using a junk power supply. I will see if I can borrow an oem power supply later this evening and will update after trying that.

thanks again

Hope that helps! Let me know what the results are.

I was not able to borrow one. I ordered the Nintendo brand power cable and the picture is crystal clear. Problem solved. Thanks for the advice.

Yet another case of cheap third party adapters with improper current ratings causing issues with consoles!

I'm glad you were able to solve your problem. I will say that the third party adapter might have caused extra wear to the caps, but it should work just fine now.

i was going to say it sounds like a crap power supply. good luck fixing it!