OG Famicom AV mod revisited...

So, about 8 years ago, I attempted to AV mod my OG Famicom. It wasn't my best work, but it worked for what it's worth.

Fast forward to a few weeks ago. I brought it out to take out the PPU to copper tape wrap it to help cut down the jail bar effect. Even after applying the copper tape to the PPU and grounding it, the OG Famicom still had jail bars.

...

I realized that the mod that I was following hasn't been updated since 2012. I searched online for more updated mods to the Famicom mod. What I ended up finding was a more simplified AV mod and a board that matched it. 

I ordered up the parts needed for the mod, including the PCB for it, which took about a week to get everything delivered. I spent last evening getting the PCBs populated and finally installed in the OG Famicom.

This is the old mod removed from the system. I just realized that there has been a few iterations of the mod since the first attempt 8 years ago. I still used the PNP transistor from the Famicom itself, as well as a different capacitors. Pin 21 on the PPU was also lifted and isolated from the mainboard.

Here is the latest iteration of the AV mod. Using SMD components, the mod itself occupies a smaller space. I also added a 220uF cap across pins 20 and 22. I also eliminated the thick shielded cable that I used for the original mod, which made it easier to route the signal wires to the proper points.

I used my larger CRT TV and a smaller LCD TV for testing for the initial mod 8 years ago. With the CRT, the jail bars were slightly noticeable. With the LCD, it was really noticeable. For recent tests, I used my RetroTINK x2 and x5 to my computer monitor. The old mod had noticeable jail bars on both the 2x and the 5x. Forcing scanlines on both devices helped hide the jail bars a little. The 5x, with some tinkering with settings, eliminated the jail bars enough that it wasn't prominent.

With the new mod and the 5x, I couldn't see any jail bars. Not really a pristine image, but with a few tweaks with the 5x settings, it eliminated majority of the jail bar effect.

So, yay! I think the AV mod can only get better from here. Maybe slapping an NESRGB in there?

I may have one more post before the end of 2021. Stay tuned!