What's the deal with this Commodore 1702 monitor..?

[armonigann]

Hey everyone,
I'm having some issues with this 1702.

So I have this awesome 1702 I bought for 20 bucks in excellent condition around Christmas, and decided to finally hook up some consoles to it...my outcome..

NES: picture looks great with famicom carts with adapter, also looks and plays great with unlicensed titles(tengen carts).......but, any regular NTSC carts, gives me wavy lines like I'm using RF..

Snes: everything is all good...slight ghosting, but still good picture and sound..

Turbografx 16: same as Snes..

Sega Genesis model 1 : On all carts, go to title screen, then goes to scramble mess..

Sega Master model 1 : exact same as sega genesis..

Colecovision and Atari flashback 2: both look and play great.

Note: every thing has been cleaned, carts, consoles etc..each system is using official AC and AV in the front ports, with the switch on back of monitor on "front"...

Can anyone help me with this weird issue I'm having, as I would love to at least be able to play some genesis/sega master games on it....with the consoles that do work on it, as said, the picture and sound are pretty good.

Thanks in advance..

[Mitch]

Sometimes the Front/Back switch on the back gets dirty. You can hit it with some contact cleaner and see if it helps.
Make sure the monitor is off when you do that.

Mitch