RGB bypass amp on SF Jr. not working

[Joonas Suomalainen]

Hi!

I installed the RGB bypass amp 4.1 into my Super Famicom Jr., but I’m not getting any signal into my ODV-GBS-C. I’m using a PackAPunch CSYNC 470 Ohm SCART cable. I first tried it with just the J2 jumper closed and then with J3 closed too. Then finally with both open. The ODV-GBS-C isn’t recognizing any signal no matter how I wire it. The cable works with my other Super Famicom and I’m pretty sure it has CSYNC coming in from multi AV out pin 3. The scaler works with all my other consoles. I also know for a fact the console powers on and is running the game.

Can anyone point out where I might have made a mistake? Is there anything I could do to pinpoint the problem? If nothing else works, is it possible to wire R, G, B and CS into the S-RGB chip instead of the S-CPUN chip? I know the S-RGB is where you’d normally tap for S-Video, not RGB SCART, but I saw one guide for an older amp board that had CSYNC wired from the S-RGB chip straight to multi AV pin 3. Could I try that?

• This topic was modified 1 day, 14 hours ago by Joonas Suomalainen.

[Joonas Suomalainen]

I did some testing. If I put a jumper wire between the CS pad and multi AV out pin 3, the scaler picks up the CSYNC and I get picture and sound as intended. Also, if I put a jumper wire between the CS pad and the left side pad of J3, the scaler picks up the CSYNC. So does this mean the problem is that the CS pad isn’t connected to the right side pad of J3 internally? How would I test why this is the case? Or is the problem something else entirely? The picture looks great—and to my eyes exactly the same—whether I connect CS directly to pin 3 or the left side pad of J3. The weird thing is that J2 is now open, which should result in an image that’s too dark because I’m using the 470 Ohm CSYNC SCART. So I’m also bypassing J2’s resistor when I connect CS to J3?

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