OSSC noise over some inputs

[Arbaal]

Hi!

I build my OSSC from the ground up and it’s working as of right now. But there are some issues left. The main issue I have is, that some inputs (SCART(Saturn) / Component(PS2)) are noisy with green / red dots.

Sync and HDMI connection overall seems fine. VGA input of my Dreamcast also looks good and more or less noise free.

The noise gets worse, the higher I go with the line modes. Line x2 only has sporadic noise and Line x5 has noise all over the place.

OSSC Debugging

I of course looked out for bridges / shorts. Does somebody has a good starting points to debug further? I personal think that the problem may be located somewhere between the THS7353 and the TVP7002PZP, since VGA doesn’t seem to be affected.

[marqs]

That looks more like digital noise, so I’d first try another HDMI cable and if that doesn’t help, resolder all pins that connect to traces between IT6613E and HDMI socket.

[Arbaal]

Thanks for the input. I will try reflow the IT6613E and the HDMI socket as soon as I have the time to do so.

[Arbaal]

I went with over the pins between the FPGA, IT6613E and the HDMI socket with a solder iron and solder wick and reflowed the ESD protection on the HFMi traces again. This seems to resolve the problem with the digital noise.

Now I only got a problem with the OSSC not beeing able to flash the serial flash and loading the profile settings. JTAG flashing works, but maybe I have an incompatibility with the SST25VF016B I use as a replacement for the hard to get original serial flash.

But this problem here is solved now. Thanks a lot!

[Author]

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