AES screen distortion at the top

[VRC-SID]

I'm getting screen distortion at the top of the image when things get bright in the picture. Also, there is a lot of noise in the image. This is a low serial version with a Unibios 2.3 installed. I'm guessing its CAP related, but I thought I should ask.

 

[Official Ninja]

Just sounds like the normal AES sync problems. Did you try a different TV or maybe run the AES through a VCR input?

 

[Hewitson]

I bet this is on a Plasma or LCD.

Does using a VCR do much good for these? I haven't tried it, I assumed it'd just pass through the signals. What reason would there be for it to modify them?

 

[Kyuusaku]

I think this is actually caused by the Neo setting the "shadow" DAC bit which dims the screen (usually accompanied by bright white flashes) and drops below the sync level threshold with insufficient coupling. If it works on another TV or VCR input/whatever, you just need to increase the series capacitor on the composite line (100 or 220uF?) with a 470uF (or add another 100/220 in parallel.) I think the theory is that the high pass filter formed by the cap and the TV messes up clamping.

 

[Hewitson]

Hmm I'm not sure I've seen this occur even on actual TV broadcasts on a couple of sets..

 

[Official Ninja]

I bet this is on a Plasma or LCD.

Does using a VCR do much good for these? I haven't tried it, I assumed it'd just pass through the signals. What reason would there be for it to modify them?

I have some cheaper VCRs that simply pass thru the signal and doesnt help at all.
I also have a few JVC and Pioneer VCRs that must process the signal somehow, because they fix the AES sync problem. In particular one JVC VCR I have makes the picture look great ever over composite on a LCD screen.

 

[VRC-SID]

Confirmed. Was running it on a HDTV in both cases, but looks great on my CRT setup.