Any ideas what could be causing these horizontal lines?

[pushead]

Hi,

I've installed the RF-replacement (analog only). But I see that the picture is a bit distorted. If you see the pictures attached you'll see that there are some re-occuring horizontal lines which are most visible when the screen is dark blue/light blue (default C64 screen). It's not so visible when other colors are displayed.

My TV only support Composite by SCART unfortunately. So I can't test properly with S-video.

Any ideas what could cause this?

BR,
Arne

Strange horizontal lines:

Looks ok:

Looks ok:

[ikrananka]

This looks like it is likely to be related to Issue #38 and Issue #53. If so, the solution is a timing mod which is board dependent. Best to read through those two issues and watch the videos, in particular this one https://youtu.be/oo_gWjK-gGw?t=2232.

[c0pperdragon]

If I inderstand this correctly, you are just using the original analog output of the VIC-II here (with a simple analog-only amplifier board?). When you really have to use the composite output, there is not much you can do to improve the matter any further.

The way composite modulates the color information into the luminance creates a signal that can not be perfectly seperated. This is most noticable on high-contrast edges, where the TV can not really guess wheter this signal is meant as a change of brightness or color. This is the reason why s-video was invented and was later superseeded by component video.

[pushead]

Ok! Thanks for feedback! I've ordered a S-video cable also for my C64 to check if that helps. Doing some testing on another TV:-)! Thanks! tir. 18. jan. 2022 kl. 16:25 skrev c0pperdragon ***@***.***>:

…

If I inderstand this correctly, you are just using the original analog output of the VIC-II here (with a simple analog-only amplifier board?). When you really have to use the composite output, there is not much you can do to improve the matter any further. The way composite modulates the color information into the luminance creates a signal that can not be perfectly seperated. This is most noticable on high-contrast edges, where the TV can not really guess wheter this signal is meant as a change of brightness or color. This is the reason why s-video was invented and was later superseeded by component video. — Reply to this email directly, view it on GitHub <#78 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AIBD5NKBGWMZ2KEKS4MCWLDUWWA5BANCNFSM5MHE6YCA> . Triage notifications on the go with GitHub Mobile for iOS <https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android <https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub>. You are receiving this because you authored the thread.Message ID: ***@***.***>