I'm not specifically familiar with the mod you're doing, but I've done my own share of mods on the OG NES, so I've been there before.
Regarding what you're doing, I found an interesting picture that you might be familiar with or not.
[image|3196061]
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Based on that, I'm a little concerned about your "K" connection to the board. There seems to be a lot more exposed wire than is necessary, and I'm afraid that bare wire is touching another resistor and possibly causing problems.
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[image|3196063]
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The only other thing that stands out to me is the concern about the resistor that's called for on the "J" line. I suspect yours is there on the circuit board but can't tell from your photo. I assume it's in the spot pointed to by the arrow in this picture.
I'm not specifically familiar with the mod you're doing, but I've done my own share of mods on the OG NES, so I've been there before.
Regarding what you're doing, I found an interesting picture that you might be familiar with or not.
[image|3196061]