Famicom A/V Help!

[133MHz]

No problem with the plastic casing .

[petik1]

OK. I suppose this is all wrapped  up... Now, should I get a SFC or SNES in the future?

[famiac]

Get an SNES because with the snes you can drill out the nubs and make it regione free! (you can play sfc games on it) Wherea you cannot make an SFC region free.

[petik1]

Ok, but I cant find  cheap one. I found a SFC with one controller for 18.89! I have the AV out and Power supply to match it and I want to get Mother 2.

[Ipergorilla]

Hello, i have some problems with my av mod...

I got a Famicom from a friend of mine who went to japan. I live in Italy and thus i have a PAL tv set

I found this little guide that shows how to do the mod: http://www.h3.dion.ne.jp/~kuboken/famicom/famav2.html
it was helpful since my famicom has the same board design as the one in the pictures.

but there are some differences in the schematics:

- It says to use a 0.47µF condenser instead of a 47µF one.
- it doesn't contemplate the 75Ohm resistor
- it doesn't contemplate the condenser in the audio circuit

I also bought on of those universal power converters, and set it to 10V voltage with the negative pole in the central pin, as per the specifications I found here on Famicom World (http://famicomworld.com/workshop/tech/famicom-power-adaptor/). The amperage is higher than the original specifications but, as fa as I'm aware, that shouldn't be a problem!

Now, I think i did a mess! I soldered everything just like in this picture (that's just the Video signal):


But instead of the 0.47µF condenser, i used a 47µF one!

then I tried to hook the Famicom up to the TV, with a game in it. When I first turned it up, the tv showed a grey-ish screen (no color) with some glichy squares.
I tried then to turn it off and on again, but all I saw then an in all the following attempts was a black screen! Have I fried my Famicom?

[ericj]

Show us a pic of your actual mod. Are you sure you have the transistor hooked up correctly (and not reversed)?

[Ipergorilla]

actually, I was kinda upset and I thought I screw up the famicom so i unsoldered the mod... Anyway i checked the transistor many times before soldering it.

The thing that made me worry the most is deeing the first screen and then seeing black all the times i retried to turn the fami on...I'm no electrotechnician, so the thing I'm mostly concerned about is that I may have damaged the Famicom irreversibly... Can that happen, by just soldering the wrong components to the right spots?

One other thing that could've gone wrong is that maybe i overheated one of the resistors while soldering (it's like the second time i ever solder)... that would be a relief since it would mean that i just need to spend a couple of more euros to buy the new components..

Also, now i've found at least 4 different schematics for this same AV mod, all involving different condensers and resistors: the one 133mhz posted, the one i linked above, then this, then this (wich also has different solder points)... I'm very confused

I'm not even sure if it's worth it trying again, since i don't know if my famicom is fried or not... what do you think?

[ericj]

Check the voltage on the cart connector and see if you get a reading. If so, you didn't fry it. I think it would be highly unlikely you would ruin it by incorrectly soldering the parts, but you could feasibly trip the fuse or burn out the voltage regulator. They're easy fixes if you did.

The mod on the site you linked to is pretty good and not too hard to follow. Although to me it looks like it'd be pretty easy to short-circuit something since there are all those ground points right by where you're soldering everything. I did roughly the same mod but used wires to connect to the points on the PCB so I could put the majority of it out of the way.

Just make sure the polarity is correct on your cap and the emitter, collector,and base on your transistor are correct, and you should be good to go. The board revision you have if you followed the version on the linked site is different than the schematic posted by 133.

[Ipergorilla]

The board revision you have if you followed the version on the linked site is different than the schematic posted by 133.

*facepalm*

Ok. Which pin should I check on the cart connector? also... where's the fuse on the famicom board? @_@
Thanks a lot for the help... you have no idea how conforting this is to me!

[ericj]

The pinout sheet is here: http://benheck.com/Downloads/NES_Famicom_Pinouts.pdf

You'd be looking at pin #1 & pin #31. Basically on opposite ends of the cart slot.

The fuse is under the metal box. It's the rectangular black box thing on the left-hand side in the pic:

[JBK Games]

I am very interested in a tutorial with high res pictures that show how you can adjust the video inductor coil for optimal picture quality.  I have a theory that adjusting the RF coils and insulating the traces for video will significantly reduce the  vertical line problems.  I wrote a post on retro gaming roundtable regarding how I did this to one of my famicom top loaders and significantly reduced the vertical line problem, although now there is a bit if "swimming" noise and I have not found the time nor means to correct this swimming issue. 

http://www.digitpress.com/forum/showpost.php?p=1746754&postcount=25