To get expansion audio from the cart to your NES you need to add a resistor inside your front loader.   Put a 47k resistor between pins 3 and 9 of the NES expansion connector.  The resistor value can be changed to get different volume on that channel, so an adjustable potentiometer is probably best.

Ironically, I just did this mod yesterday. I went a little different route and totally desoldered the expansion connector.

Just finished this mod.... all went well I think...... what's the best way to test? The sound on Akumajou Densetsu sounds great but I haven't listened to it much previously.... Will post a picture in a second.





At first I read Underside of the board but I didn't think there would be anything to solder to.... I'm very new at this so I just went with the first picture.....

Looks good. Try the Famicom disc game doki doki panic (super mario 2). When you kill off the enemies they make a funny scream

Thx Mog, booting it up now

Edit: annnnnnd works like a charm. Thanks for the original info everyone, gonna finally sit down and smoke CV 3.

If someone was to buy a PowerPak in the future, would this be a little extra option for $5 more or whatever?

This is a mod for your NES not for the PowerPak.  However there was someone looking into getting expansion slot connectors and selling "resistor mods".  It's pretty simple and easy to do.  About as easy as electronics can get.

Can you offer a tutorial with potentiometer installation included?

It's as simple as putting the pot between the two pins instead of the resistor.  Doesn't really need a tutorial.

I did this mod. It is super easy i installed a push button on the front of my nes. That way i can turn it on or off to show the diffrence to my friends. I dont think i would put a pot on there. It is a cool little mod.

Scott

has anyone ever had issues with the mod working for a few minutes then not working? any help would be great...thanks!

I know this thread is a bit old but does anyone have the instructions to do this for a top loader?

http://forums.nesdev.com/viewtopi...

and SavePointVG, it sounds like you have a bad solder joint(s). Try resoldering it.

Hey everyone,

sorry to bump an older thread but I really need some help here.

I had this mod done so I could enjoy this extra audio channel on a "Mr Gimmick" reproduction (which is, of course, marked as such). It's a very simple operation, it seems, and the guy who did it for me didn't want a lot of money for it. However...it's not working. The sound effects of the shooting stars, jumping and so on are still missing.

It shouldn't be the game's fault since it did have the effects when the guy who made it tested it before sending it to me. However, I'm told it is unlikely the resistor is defective, and installing it doesn't present many opportunities for mistakes. But what could it be? What can I do?

I am using a front loader US system with RGB mod.

Mr Gimmicks extra channel is real quiet, are you sure its missing and just not real low volume? What value resistor was used?

Since you're playing a reproduction and not on a powerpak , you may need to add another jumper wire to some other pins. I ran into the same issue when I got Akumajo Densetsu  (Castlevania III) on the famicom.  There's a solution to it here. I'm not 100% sure That's your issue but it's worth a shot

Sorry for the necro-bump. Placing a pot inline will work but it won't give you full control of the volume. A better way is to connect a 10k audio tapered pot set up as a voltage divider:

Pin 1 on the pot goes to ground (PIN #2 on the expansion connector). The center pin on the pot goes to the AUX audio port on the NES (PIN #3 on the expansion connector). The third pin on the pot goes to the the data pin 6 on the NES slot (PIN #9 on the expansion connector).

I installed the audio pot along with a nice big red knob on my NES, directly above the controller ports. I find that audio is balanced with the pot set at the 2/3 position (clockwise is full loudness or 100% and counter-clockwise is off or 0%). I also placed two 10uF electrolytic caps inline with the input and output pins on the pot (negative side faces the pot which is grounded) to isolate any possible DC bias and provide a hi-pass cutoff around 10Hz, although it probably isn't necessary.

Since we're in a thread involving opening up and modding a front-loader, I have a question...

So I swapped my ZIF connector a couple months back, but couldn't get the damn RF shield back into the system (at least, I'm assuming the big-ass hunk of metal covering everything was an RF shield).

Now, I don't use the RF generated signal, and have the RCA plugs hooked up to an adjacent CRT.





Do I face any unforeseen issues from NOT having an RF shield installed if I'm not using the RF signal?

Am I bombarding myself with some undesirable quantity of radio waves at a known hazardous intensity/frequency?

I wouldn't worry about it.  I have noticed that if you use RF then it will make a difference in the quality of output, but I've seen no ill effect to composite output.

Thanks.  

I was more concerned about if anybody knew of the emission intensity and frequency to be potentially hazardous, but doing some cursory searches it looks like the 400-600 MHz range is used for Analog TV signals, and I suspect this system outputs on the lower end of that range since it only generates Channel 3 or Channel 4.

Just didn't want to be bombarding myself with unshielded microwave radiation or something crazy like that

interesting that this thread came up again ... I did millerjm2's mod for the retro-bit RES nes clone system, and CV3 came out odd... i got the expanded audio, however now all the 'sound effect' are extremely muted .. must have something to do with the resistors i added ... i put two resistors inline to approximate 1.5 ohms (or whatever it was that was required) ... I wonder if something like the thread you linked would fix that as well.. very cool

Dude, didn't you hear? The NES is plutonium powered and if you remove the heavy lead shielding, you'll expose your self to lethal doses of radiation. Did you plug it in without the shield? You'll probably get radiation sickness and die. Did you play it for more than an hour? I'll give you a month tops...

LOL!

Yes your NES will run just fine without the shields although it may void your FCC license to operate it, like that matters anymore. You may have slightly more A/V noise and your system might be suseptible to EMP damage if a "nukular" warhead detonates nearby. But if an atom bomb went off in my backyard, I'd have more important things to worry about than if my game consoles survived.

I'm going to necropost again; after I mod expansion ports 3 and 9, what do I have to do on my 60-pin converter?

N the Bit Gamer .. check out the attachment, that what you are looking for ?

Yep, this is exactly what I was looking for! Thanks!