Black screen in Yoshi's Island (SNES)

[exec]

Hello. I have a weird issue with my SNES and (new) OSSC. I’ve just been playing some games randomly, and generally everything’s working great, with the SNES and other systems, but when I start up Yoshi’s Island (PAL), right after the Nintendo logo, where the story is told, the OSSC apparently loses sync (red light). No audio, no video.

Now when I press start immediately after the screen went black, I get to the title screen and everything’s fine, but if I wait a few minutes and then press start, I do get sync again, but still no audio and only static as video. It stays that way until I restart the SNES. This does not happen when I connect the SNES directly to the TV via SCART.

I can live with having to skip the intro, but I’m a little worried about my SNES^^” Is this a common problem? Can I do something about it? Or is maybe something wrong with the OSSC?

Thanks,
exec

[BuckoA51]

which type of SNES (1-chip or multichip?)

[exec]

I can’t open it, for lack of tools, but based on the “open expansion slot and look for dots” method (http://www.retrorgb.com/1chipsnes.html) it appears to be a 1-chip, as I don’t have those dots. The model is SNSP-001A(FRG), serial UP18275805.

Edit: From The Lion King debug menu:
– CPU: 2
– PPU1: 1
– PPU2: 3

[paulb_nl]

I was able to reproduce this. It happened to me when Analog sync LPF was not on 2.5MHz. If it still happens after that you can increase Analog sync Vth to fix it.

Are you using a luma sync RGB cable?

[exec]

Thanks, paulb_nl, increasing sync Vth (to at least 146 in my case) does indeed solve the issue, sync LPF was at 2.5 already. Could leaving sync Vth at this cause other issues? (Since it’s listed as a last resort option on the wiki.)

I’m using the standard cable that came with the SNES right now, though I ordered a luma sync cable recently. Could that solve the problem as well?

[paulb_nl]

I am not sure if changing sync Vth could cause other issues because I have not tested it much yet.

You should be able to leave sync Vth at default with a luma sync cable for this game. However I recently found that with my luma cable I have to increase sync Vth or else Donkey kong country will lose sync during the explosion on the title screen.

[BuckoA51]

No issues here on my console.. 1 chip US model with SuperCIC and RGB amp/brightness fix installed, set to PAL, PAL copy of the game. Cable is a Pack a Punch clean CSYNC.

[exec]

Got the same issue with Donkey Kong Country, had to increase sync Vth to 225. Though it doesn’t happen the first time I watch the intro, only on subsequent runs. I think it’s not the explosion, but that roll-up effect of the title screen that follows it, which is not used the first time. But at least DKC resyncs after 2-3 seconds, unlike Yoshi’s Island, probably because the intro scene there is minutes long, causing more problems at some point.

My SNES is an unmodified PAL model.

Now I’m curious how much of a difference the shielded luma cable I ordered will make once it arrives, if any. If only a PACKAPUNCH cable fixes this I might have to upgrade once more^^”

[BuckoA51]

There was one game that used to do strange things on my multichip during the intro that was Arkanoid – Revenge of Doh.

I’ll hook up my multichip and not so good RGB cable and give it a go.

[exec]

Got my luma cable from Retro Gaming Cables today. The result: the Yoshi’s Island intro now works with the default (sync Vth 123), and for Donkey Kong Country I only need 191, instead of 225 like before, so I can confirm that the cable seems to make a difference, and can potentially fix the issue. A little weird was that on the first try I got static right away from Yoshi’s Island, with no sync at all, but who knows what that was, it worked after testing DKC.

I’ll leave sync Vth at 191 for now, and I’ll report if that causes any issues. I’ll hold off on buying a PACKAPUNCH unless I notice any problems, since I’m pleased with the image I get through the new cable. Thank you guys, I had already ordered the cable, but I didn’t think that the problem might originate there^^

In case it’s of interest to anyone, I’m usually using a cheap, like 10€, SCART switcher for convenience (no noticeable quality difference from 1-2m away), and connecting directly to the OSSC didn’t make a difference in the required sync Vth values.

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