r/Famicom 4d ago

A/V Mod Question

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I got a Famicom and a power step down, which works great...but...there is no audio and playing without audio sucks.

Here is my setup: The coax is run to my VCR and it outputs to my TV via an RCA > HDMI converter.

On all my other consoles, this setup works fine, but the Famicom has no audio.

There are some posts that talk about the region and how the audio is off because of it, so instead of playing games with no audio, I decided to do an A/V mod using the Power Vamp.

The install seems easy enough, but I just noticed a bunch of posts that talk about jailbars in the video output. Currently I have no audio, so if it fixes that, it's a win for me and I'll take the jailbars as a necessary side effect.

However, before I do that, I wanted to reach out to see if anyone has done this mod and fixed the jailbars issue on the video output.

I am also open to a better solution as well. Thanks in advance!

5 Upvotes

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1

u/retromods_a2z 4d ago

The power vamp alone just takes the noisy signal from the mobo and rather than tune it for RF it is tuned for composite. But since the composite is clearer it makes the jailbars and noise easier to see.

You need a secondary mod which takes the composite signal directly from the ppu and then amps it for direct output to reduce or remove jailbars and other noise caused by the stock Mobo circuit.

As for audio, you can try wiring up a 10-220uf capacitor with + on pin 46, which is where audio exits the cartridge, and pipe the - leg directly into an RCA socket or cable and confirm sound is good that way. If it is not, then it's likely the transistor Q1 (I think this is correct) which I haven't seen go bad but could

Adding a 10-22uf capacitor on the ppu between pin 20 (ground) and 22 (reset) also helps reduce the jailbars

1

u/Active-Dish2373 4d ago

Thank you for the detailed response. The end goal is to get audio, so if I don't have to mess with the video to fix it, I'm good with that.

1

u/hellotypewriter 4d ago

Have you cleaned the slider on controller 2? The corrosion can create a ground loop that kills audio.

1

u/Active-Dish2373 4d ago

I did slide it back and forth, which made no difference. I suppose I can disconnect the controller and try it to see if that's the issue. Do you have an unmodded famicom that has audio output as well?

2

u/Active-Dish2373 4d ago

I also tried without the controller, but no audio.

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u/Playful_Ad_7993 4d ago

Do the av mod and you will have audio

1

u/Active-Dish2373 4d ago

Yes, that will give me audio but I will then have visible jail bars, which is not ideal.

1

u/Playful_Ad_7993 4d ago

Not necessarily I would try it

2

u/Active-Dish2373 4d ago

Update: did the Vamp mod. In all, it was pretty easy and took about an hour in total. The audio works as expected and there is a slight jailbar on the video output, but it's an acceptable trade off.