Mega Drive Image Problems

[odrakir]

Hi guys,

I recently bought an used MD1 to replace the board on my old one (which only displays a black image).

I tested the used MD1 with the RF cable and I got a little distortion on the image from now and then, specially on games like Sonic I and II. Yesterday I got 2 RGB cables, one for the MD and another for my Nomad.

The picture quality on the Nomad is great, but the MD still has the same distortion and it shifts the screen a few pixels between left and right.

I've uploaded a video showing the problem here -http://www.youtube.com/watch?v=SjOk94jH2zM

Is this a known problem on the MD / Genesis?

Thanks!

[drmay]

I couldn't tell because the camera was moving too much.

But there shouldn't be distortion like you described. I have seen where the video encoder chip was going bad that did stuff that sounds like you described. Nothing to do for that except get a new Genesis/MD. They're pretty cheap at thrift stores.

[odrakir]

Thanks!

Can this be caused by a bad RGB Scart cable? If you play the youtube video on 480p or 720p you can see what I described above, specially when the Sonic II opening screen shows up.

[FABombjoy]

I would try the MD on a completely different TV. My first instinct is to blame the video processor in the LCD TV for not properly processing the signal from the MD, but it could be the MD itself.

I can't see this left-right thing, but I can see what looks like an occasional vertical sync issue during the title sequence. Both issues could be caused by a bad / misinterpreted CSYNC signal. I did a quick google for "cxa1145 csync" and found a few other forums with people having all manner of sync issues with modern TVs and the MD/Genesis/SMS.

[odrakir]

I tested a Nomad with a scart RGB cable on the same LCD TV and there was no problem at all. Isn't the signal the same?

Thanks!

[FABombjoy]

It uses a different RGB encoder (CXA1645 vs CXA1145)

[drmay]

A lot of Genesis/MD games don't display correctly on most flat panel TVs. I don't know the technical reasons for that but they don't. You'll get disappearing or flickering sprites. It is either just a different decoder or a bad decoder. I would try playing it on a CRT TV and see if you have the same problems.

[Esther Imaging]

maybe this is the known probelem of on the MD, or maybe it just baceuse it is secondhand.....

[theclaw]

I tested a Nomad with a scart RGB cable on the same LCD TV and there was no problem at all. Isn't the signal the same?

Thanks!

Nomad was released 60hz exclusive.

If your problem only happens with a 50hz version MD, it might be part of the issue.