Static blue image with some vertical lines on N64 Advanced VGA output

[milosonator]

I’m having an issue with the video output on my N64 Advanced. It seems to output a bad image, even though it looks like a valid VGA output, and the screen syncs correctly. It’s a mostly blue image with some vertical lines it seems:

I’ve installed the N64 using the flex cable on a PAL N64, no jumpers are set, I’m using normal VGA output (h/v sync lines, RGB and GND). The composite output of the N64 is good. It’s hooked up to the same screen and switching between inputs shows the good output, but on the N64 Advanced, it’s wrong.

Any help with debugging this issue would be greatly appreciated. Seems perhaps there is some bad data coming from the N64?

I’ve checked the connections, but not sure if there is something I’m missing. I’ve got the flex connected, and the 5V line to the N64 5V regulator. Other than that I have my VGA outputs hooked up to the screen. 5V, 3.3V and GND all verified. Not sure how to verify the other lines, since they seem to pass through some components on the flex.

Album with images: Album

[milosonator]

Update: depending on the scene shown (running Mario 64, it plays through a couple of demo scenes) the image in the certer vertical ‘bar’ shows a variety of moving/changing, vertical lines. So some data is making it through.

[BuckoA51]

No jumpers set.. hmm, don’t you need to set jumpers for line double mode if you’re using a VGA monitor?

[milosonator]

The manual says the following:

> J4.1: – opened: linedoubling enabled

Therefore, I have left the jumper open.

[BuckoA51]

Did you ever figure this one out?

[milosonator]

Unfortunately, I have not figured this out… So if you have any ideas on what this could be or approached how to debug, I’m all ears.

[BuckoA51]

Did you get the board from us? Have you tried connecting to a different display?

[milosonator]

Yes I did acquire the board from VGP. I will try another display as a next step of trying to resolve this issue.

[milosonator]

I’ve tried again with a different display and with a different Nintendo and the N64A now works correctly.

I’ve then tried with a similar screen (but different unit), that worked too. So either the problem is with the original screen, the original Nintendo, or my wiring 😎.

Biggest difference is that I tried now with an NTSC Nintendo 64 rather than a PAL one. So one plausible explanation is that the original display didn’t support whatever display was being output.

Either way the N64A is working, and especially on 240p the image is crispy.

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