Getting Famicom Expansion Audio working on Eng Top Loader with RGB & Audio Mod?

greedostick

Obsessed Neo-Fan
15 Year Member
Joined
Aug 11, 2003
Posts
4,474
I have a RGB modded English Top Loader with Expansion Audio Mod. English NES carts are working fine such as Gimmick Repro with Expansion Audio, and NES Everdrive.

Not working are Famicom games such as Dracula's Curse, or Famicom Everdrive N8 games.

1. I have an adapter to play Famicom on NES, that has been modified for expansion audio. The expansion audio works fine on a modded toaster using this adapter. Not working on my top loader?

2. Tried on another friends modded English top loader. It's not working on his as well. Our systems were modded by different people. He modded his own. He tested the audio toggle with a multimeter, and our mods are exactly the same, even the resistors used.

Any ideas on how to get both the NES and Famicom expansion audio working?

Do you think it's a problem with a modded adapter, or the way our consoles are modded?

Is this even possible?
 
Last edited:

MobiusStripTech

Mr. Big's Thug
Joined
Dec 4, 2017
Posts
201
Without seeing how your mod was done, I can only guess. So a few things to look at. If you are using the amplified audio from the NESRGB board, then you need to route a resistor into that audio circuit from pin 51 of the toploader. If I recall correctly it should be 47k ohm. If you are not using the audio from the NESRGB board, then as long as you have the resistor from pin 51 connected to the audio you are feeding out of the system, you should be fine. In the famicom to nes cart adapter you shouldn't be adding any resistors, all you need is to connect pin 46 of the famicom side to pin 51 of the nes side. You may also need to connect pin 54 to pin 51 on the nes side for MMC5, but that depends on your setup and the cart adapter.

If you are using the NESRGB audio, Tim states that you really should build a different audio circuit to use with his amplified circuit. Here is a link to the circuit Tim says to use for the NESRGB board. https://shmups.system11.org/viewtopic.php?p=1115605#p1115605
 

greedostick

Obsessed Neo-Fan
15 Year Member
Joined
Aug 11, 2003
Posts
4,474
Without seeing how your mod was done, I can only guess. So a few things to look at. If you are using the amplified audio from the NESRGB board, then you need to route a resistor into that audio circuit from pin 51 of the toploader. If I recall correctly it should be 47k ohm. If you are not using the audio from the NESRGB board, then as long as you have the resistor from pin 51 connected to the audio you are feeding out of the system, you should be fine. In the famicom to nes cart adapter you shouldn't be adding any resistors, all you need is to connect pin 46 of the famicom side to pin 51 of the nes side. You may also need to connect pin 54 to pin 51 on the nes side for MMC5, but that depends on your setup and the cart adapter.

If you are using the NESRGB audio, Tim states that you really should build a different audio circuit to use with his amplified circuit. Here is a link to the circuit Tim says to use for the NESRGB board. https://shmups.system11.org/viewtopic.php?p=1115605#p1115605

I sent my friend your reply and it worked. Thanks!
 
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