Nes to FC adapter compatibility fix + powerpak audio wiring

Posts : 9 Join date : 2012-02-09

Hi all,

This post isn't necessarily completely related to this thread but since it had the supporting images that I needed, I thought it'd be a great fit. I have several different 60-72 pins converters, the Yobo, Family Convertor and a replica of the one shown here. Unfortunately I don't have the nice case to go along with it. But regardless, the first one I bought blindly was the Yobo. It is totally useless in the AV Famicom, it took me about a half hour to get a single game to show up once. I did a lot of research on the subject and inspected the board and decided it was too far off from what would be the ideal convertor so I bought a Family Convertor, worked right off the bat. A few weeks later, I found on eBay, one just like the one in this thread, but a replica. This one is great, you don't have to have the cartridge reversed in the slot when you play it. I did however have to replace the NES connector since it had the wrong pitch. As far as I know no one knows where to source these connectors from. I stole the one from the Yobo and installed it, now it works great.

I know this is a long story, but what I wanted to say is that in all of this debacle, I had the chance to compare the circuits of the different boards and do a lot of research. Ben Heck actually has a document that shows the NES pinout and the Famicom pinout. One flaw that this connector has is pin 31 on the Famicom side (+5V) is connected with pin 37 on the NES side (Clock), this is wrong. The Family Convertor has this right, the Clock pin should not be connected to anything. I'm going from memory here, but I think even the Yobo had it right. I actually cut the trace on my converter and it works correctly, not to say that it didn't work correctly before. Chances are that a only a few games (if any) are even using the Clock pin. I can understand why converter makers thought it needed to be connected, the opposing pins on the 4 corners are strategically GND and +5V, so if you were to insert it the wrong way, you would not be reversing the power on your cartridge and blowing your chips.

Nic

Uhh....so do these nicer adapters have clock wired into 5v? It's kind of hard to plug it in the wrong way when it's in a nice cartridge slot sized case cool

Posts : 9 Join date : 2012-02-09

Quote :: Uhh....so do these nicer adapters have clock wired into 5v? It's kind of hard to plug it in the wrong way when it's in a nice cartridge slot sized case

Yup they do, but like I said, I suspect the number of games that make use of that signal is extremely limited (if any, I don't know of any), so on the NES side, games would likely not be wired on that pin. It's just that it's *technically* incorrect.

I threw in the story about reversing the connector because the popular Family Convertor does not come with a case. So you could theoretically still do that.

Nic

So is it improper wiring or unnecessary wiring? Is there any harm leaving it wired up the way it is?

Posts : 9 Join date : 2012-02-09

I doubt there are many games that make use of that pin, I don't know what it would be used for either, so it's hard for me to quantify what would be the risk but it's probably a very slim risk. Most likely carts don't even have the gold connector pin or it's not connected to anything inside. I believe this is an improper wiring on the converter. You can check Ben Heck's document here: www.benheck.com/Downloads/NES_Famicom_Pinouts.pdf Now don't take this document as a reference for what needs to be connected where, it is just a listing of pins that's been aligned between NES and Famicom so it's easier to read. You can also look at the PCB of the Famicom Convertor ot the Yobo converter, that pin is just not connected at all.

Personaly, I modified mine the same time I fixed it to work with the advanced audio, I was already going to work on it, so why not make it a bit better.

Hope this helps

I don't get why it makes it better all my games work on my converter without your mod confused

Posts : 9 Join date : 2012-02-09

Well if you stumble upon a cart that makes use of the clock signal on pin 37, you'd be putting 5 volts on that line instead. Again, I don't think many games use this clock signal, if any. Perhaps some devices or other special carts you might plug in there could use it. If you're sticking with just regular games you're probably very safe.

wow, didn't notice there's a clock signal on the cartridge connector. That's odd.