Wavy lines on screen when using one battery set - resolution

[bacteria]

When you have a portable handheld console you're running console and screen off one battery source. Problem i'm finding is there are minor wavy diagonal lines on the screen when running console and screen off of one battery source, and not getting this issue if I run the screen off a 2nd battery set - so has to be down to using one battery pack thats introducing the interference. Seem to get some wavy lines on two battery sources but not as much was with one.

This is annoying and I can't work out how to get a nice non-wavy screen image - anyone know how to resolve? Using 7.4v Li-ion batteries BTW; powering N64 console and of course screen.

[CRTGAMER]

Throwing darts but maybe some Diodes thrown in for the power leads to the console? A trick of not cutting down the resistance when installing the "check valves", might drop the voltage.

[bacteria]

Tried a diode (Zener) didn't help.

[Hobie-wan]

Assuming you're using battery pack with a protection circuit in it, maybe a crappy capacitor?

[bacteria]

The answer was interesting.

I used shielded cable for the video line, and connected the shielding to the ground on the console.

To cure the problem, also had to connect the shielding ground to the video ground at the other end. The console and screen groundings were connected before, however turned out needed to do that on the shielded video cable too.

BTW, like my new sig?

[Hobie-wan]

Glad you got it resolved. I'd still guess it was coming from the protection circuit since it was different across the batteries.

And yes, sig looks good.