SNES with CRT tv input issues

[peppersmith45]

I'm hoping someone can help me solve a problem here, forgive me if this isn't the right forum. I have two Super Nintendo consoles (one American and one Japanese version) that I've been testing with different TVs because of a controller input issue. The input issue is the shoulder buttons will activate while pressing other buttons, i.e. weapons will switch in Mega Man X while dashing or shooting. I have no input issues with any HDTVs I've tried, but I've tried 4 different CRT tvs and only 1 of them was free of this input issue. Is there anyone who can explain to me why this might be occurring and if there are any solutions to it? Thanks in advanced

 

[Tony Stewart]

It appears to be a transient pulse on contact sensor ( carbon type switch?)

Most likely the common mode noise on the CRT TV connection is worse.

Get a large ferrite clam-shell choke for controller cable or video cable to TV to get rid of stray CM noise. VGA cables always have these.

Check ground connection to power outlet to Nintendo.