Author Topic: Nes (72-pin) to Famicom (60-pin) converter mod  (Read 5370 times)

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Offline Barawer

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Nes (72-pin) to Famicom (60-pin) converter mod
« on: May 14, 2016, 11:33 am »
Now updated with compatibility fix, thanks to GadgetUK! check out his YouTube channel!

I recently bought myself a Famicom AV to be RGB modded later on. I had the N8 Nes edition, and didn't want to buy another Everdrive or trade it for a Famicom edition, so i bought a converter.
As you know, the converters don't support expansion audio or MMC5 games, but mods are available to restore functionality.
After following a guide, i saw that it didn't really work, so i looked for another guide.. in the end i found 4 guides saying different stuff. only one really worked, so i decided to show you guys exactly what to do. here we go:

What you need:
Soldering Iron and basic soldering skill
Solder
Wire, i recommend Kynar wire
2 10k ohm resistors (you can try out different ones, but the 10K are usually the one recommended)
Copper Tape
Phillips head screwdriver
A small file

I bought a shielded converter, and i would recommend it too.

This is the front. we will work on the back side of the converter.
Turn it around, there might be a sticker. behind the sticker there are two Philips head screws, just unscrew them.

Sadly i wasn't smart enough to take a picture before hand, so i will show you the finished mod. (as you can see i have a lot of soldering spots there, that's the main reason i wanted to make this guide)


For expansion audio:
Between pin 46 and 45 on the Famicom side, cut the connection by scraping it off (or any other method you know of)
Solder a resistor between pin 46 on the Famicom side and pin 54 on the NES side.
Solder a second resistor between pin 45 on the Famicom side, and the previous resistor leg near the Famicom side.
That's it!

For MMC5 game support:
Take two wires and cut them to size.
Cut the connection between pin 48 and pin 49 on the Famicom side buy scarping it off (or any other method you know of)
Solder one end of the wire to pin 48 on the Famicom side, and the other end to pin 57 on the NES side.
Solder one end of the other wire to pin 49 on the Famicom side, and the other to pin 58 on the NES side.
That's it!

Compatibility Fix
There were some reports of incompatibility with some of the games. A Krikzz forum user named GadgetUK has researched it and came up with a great solution. Even if you done seem to have any problems i would recommend doing this.

Now we need the front side of the converter (The side we didn't work on)


Take your copper tape and cut it to size, so it fills the entire PCB on the front but without touching any of the pins.
Tape it on and check for continuity with any of the pins. if there is, try to see where they have a connection and cut it.
Try to remove any bumps or air bubbles by going over it with something straight. If you cant make it 100% try to do it as best as you can.
Next, we need to solder the tape to pin 1 on the NES side.
This is my final result, cutting and taping is pretty bad as I'm very bad with these kind of things.


If You Bought the Shielded Converter
You will need to file some of the plastic in order to close it back up.
If you taped the copper tape just make holes in the tape using the screws.
It might be not so pretty, but i don't see any other way.
This is how i did mine:

Make sure you measure the height and width of it, so you wont file too much or too little.

When you are done, close everything, connect a game with MMC5, or the Everdrive with a game that has expansion audio support, and see if everything worked. If not, you should check that everything is connected and that the connection between the pins on the Famicom side is disconnected.

Hope it helped some of you, and thanks again to GadgetUK for the fix!


« Last Edit: September 16, 2016, 05:57 pm by Barawer »

Offline Great Hierophant

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Re: Nes (72-pin) to Famicom (60-pin) converter mod
« Reply #1 on: May 15, 2016, 01:15 am »
10K resistors are the recommended resistance, but I always thought that the internal audio was too low compared to the external, at least on a PowerPak. 
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Offline DC/AC

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Re: Nes (72-pin) to Famicom (60-pin) converter mod
« Reply #2 on: May 16, 2016, 01:00 am »
Thanks Barawer for the guide

10K resistors are the recommended resistance, but I always thought that the internal audio was too low compared to the external, at least on a PowerPak.

What resistor value do you recommend?

Offline Barawer

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Re: Nes (72-pin) to Famicom (60-pin) converter mod
« Reply #3 on: May 16, 2016, 08:39 am »
I think its a matter of testing it and seeing what you like. I didn't do much testing but 10K sound pretty good to me.
Maybe I will get a potentiometer and test some values out.

Offline fluxcore

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Re: Nes (72-pin) to Famicom (60-pin) converter mod
« Reply #4 on: May 28, 2016, 12:08 am »
For the MMC5 support, do NES-side pins 57 and 58 need to be separated? They are joined, and I'm wondering what the purpose of two wires is?

Offline Great Hierophant

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Re: Nes (72-pin) to Famicom (60-pin) converter mod
« Reply #5 on: May 28, 2016, 03:07 am »
For the MMC5 support, do NES-side pins 57 and 58 need to be separated? They are joined, and I'm wondering what the purpose of two wires is?

Yes, keep them separated on both the Famicom and the NES ends of the adapter.  They are used to control background graphics mirroring.  95% of NES and Famicom carts use standard mirroring methods and leave the two pins connected.  MMC5 can do advanced mirroring and requires the pins to be separated. 
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Offline GadgetUK

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Re: Nes (72-pin) to Famicom (60-pin) converter mod
« Reply #6 on: August 14, 2016, 12:37 am »
Just wanted to say thanks for posting this guide!  I did this today, but also added a 68pF cap to the M2 pin, which solved instabilities with my Famicom.  I was having hanging / lockups with games, and resets etc when using an N8.

https://www.youtube.com/watch?v=buLuvjwwI3s

Offline immrbig

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Re: Nes (72-pin) to Famicom (60-pin) converter mod
« Reply #7 on: August 17, 2016, 09:36 am »
Just wanted to say thanks for posting this guide!  I did this today, but also added a 68pF cap to the M2 pin, which solved instabilities with my Famicom.  I was having hanging / lockups with games, and resets etc when using an N8.

https://www.youtube.com/watch?v=buLuvjwwI3s

I saw on your YouTube video comments that you are now trying a 100 ohm resistor in series with M2. How did you make this connection? The via for this line is in an awkward spot--very far away from the NES connector and almost too close to the FC connector.

Offline GadgetUK

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Re: Nes (72-pin) to Famicom (60-pin) converter mod
« Reply #8 on: August 17, 2016, 01:23 pm »
I did two things - Firstly I lifted the M2 line on the 72 pin connector - so the pin from the 72 pin socket is not connected to the PCB, but I also made a very small cut in the trace (right next to the via on the 60 pin side), then used a wire from the M2 pin on the 72 pin connector, through a 100 ohm resistor and the other end goes to the M2 pin on the 60 pin side.   If you don't cut the trace leading to the 60 pin M2, then the trace runs in parallel with the wire and its the trace that's part of the problem.   So in summary you end up with a wire for the M2 line, running through a 100ohm resistor, and the original PCB trace should not be connected at all.  I've not been able to create any glitches or crashes / lockups since doing this.  Only time will tell whether its a perfect fix but it does seem to be working for me with my 72 pin N8 on the Famicom here.   There are so many variables and really it needs someone more experienced to take a look I think, but it does seem to have solved my problems with my Famicom.

Offline Barawer

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Re: Nes (72-pin) to Famicom (60-pin) converter mod
« Reply #9 on: August 17, 2016, 01:25 pm »
Just wanted to say thanks for posting this guide!  I did this today, but also added a 68pF cap to the M2 pin, which solved instabilities with my Famicom.  I was having hanging / lockups with games, and resets etc when using an N8.

https://www.youtube.com/watch?v=buLuvjwwI3s
Glad to help! I wonder what makes this happen, on my Fami AV it works like a charm. I cant watch your whole video right now, but i will. maybe i'll update the guide :) you did a much better soldering job than me :P

Offline GadgetUK

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Re: Nes (72-pin) to Famicom (60-pin) converter mod
« Reply #10 on: August 17, 2016, 03:46 pm »
That's really strange!  I have read about people having the same issue I had when using a 72 pin N8 with one of these adapters!  Very odd, but it is working now.  If I remove my M2 wire with the 100 ohm resistor the glitches come back.  Could be a problem related to my Famicom revisions or something - or maybe a glichy CPU or PPU perhaps.  This system has been re-capped as well.  In any case, your mods work fine =D

Offline AMike

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Re: Nes (72-pin) to Famicom (60-pin) converter mod
« Reply #11 on: August 18, 2016, 07:35 pm »
Just wanted to say thanks for posting this guide!  I did this today, but also added a 68pF cap to the M2 pin, which solved instabilities with my Famicom.  I was having hanging / lockups with games, and resets etc when using an N8.

https://www.youtube.com/watch?v=buLuvjwwI3s

Thanks for this guide - I've fixed my adapter today. Which games are the best to check? If I had understand correctly Castlevania III is one of the games.

Offline immrbig

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Re: Nes (72-pin) to Famicom (60-pin) converter mod
« Reply #12 on: August 20, 2016, 01:11 pm »
I did two things - Firstly I lifted the M2 line on the 72 pin connector - so the pin from the 72 pin socket is not connected to the PCB, but I also made a very small cut in the trace (right next to the via on the 60 pin side), then used a wire from the M2 pin on the 72 pin connector, through a 100 ohm resistor and the other end goes to the M2 pin on the 60 pin side.   If you don't cut the trace leading to the 60 pin M2, then the trace runs in parallel with the wire and its the trace that's part of the problem.   So in summary you end up with a wire for the M2 line, running through a 100ohm resistor, and the original PCB trace should not be connected at all.  I've not been able to create any glitches or crashes / lockups since doing this.  Only time will tell whether its a perfect fix but it does seem to be working for me with my 72 pin N8 on the Famicom here.   There are so many variables and really it needs someone more experienced to take a look I think, but it does seem to have solved my problems with my Famicom.

I tried your modification today, and I *think* it is working okay. Thank you! Would you mind, however, checking Metroid on your end? That was one of the games I was having trouble with, and I seem to still be getting some strange graphical anomalies and random resets.

Offline Barawer

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Re: Nes (72-pin) to Famicom (60-pin) converter mod
« Reply #13 on: August 20, 2016, 04:08 pm »
Are all of you using an original Famicom? or a a Famicom AV?

Offline GadgetUK

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Re: Nes (72-pin) to Famicom (60-pin) converter mod
« Reply #14 on: August 21, 2016, 09:00 pm »
Original Famicom!  I will check Metroid later!