Interference from power supply

[Zuul86]

I made a VGA breakout cable and hooked up a WG k7000 to a Raspberry Pi 3.  Everything seams to be working ok so far except that I'm getting interference from the power supply in the form of waves moving vertically across the picture.  I've tried three different power supplies and and range from can't even see the picture to mildly annoying.



Also, I think I need a new flyback.  The picture slowly goes out of focus and then snaps back in focus.

Any recommendations for eliminating the interference?

[elvis]

How are you getting VGA out of the RPi? Are you using a HDMI to VGA converter?  Or using the GPIO pins via something like the GertVGA666 or other "resistor ladder" device?

And regardless of which solution you're using, have you checked all your grounds are connected so you're not getting a potential difference somewhere?

[Zuul86]

I'm using a HDMI to VGA converter.  There are varying degrees of interference with different power supplies.

I think I have all the grounds connected. I'll have to verify that.

[mahuti]

Do you perhaps need one of these to convert VGA to CGA 15k? 

https://www.amazon.com/gp/product/B00XKWX4F8/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1

I think the output signal needs to be 15k... but I could be wrong. I have one of these on order for the same basic reason... converting RP2 output to an old WG CRT. I don't keep up on arcade monitors though, so the WG k7000 may not need it...

Looks like mine's a k7000 series too. I've had it sitting around since 2002... I have no idea if it even turns on. We'll see sometime in the next month. I have to get my power set up first...sigh. Parts on order.

[bleck]

The setup I currently have is
HDMI-to-VGA -> VGA-to-SCART (UMSA) -> PVM

I was noticing wavy interference on my screen too. It went away after I replaced the VGA cable with a Male-to-Male VGA coupler. My guess would be that you need better shielding on the VGA cable.

I hope this helps.

[Titchgamer]

As above I would guess you would need more shielding or move the video cables further away from any power sources.

[Zuul86]

I figured out my issue.  I got the cab and didn't realize the three hole plug with ground and composite sync was shifted down one.  So the ground wasn't connected and the composite sync was connected to ground.