nesdev.com
https://forums.nesdev.com/

Correct Famicom AV mod
https://forums.nesdev.com/viewtopic.php?f=9&t=10554
Page 2 of 2

Author:  ThePunisher [ Sat Apr 29, 2017 11:59 am ]
Post subject:  Re: Correct Famicom AV mod

infiniteneslives wrote:
Well I've had this thread bookmarked forever, and finally got around to performing the twin famicom video circuit mod to my original famicom.

Hi, friend! I've recently started collecting parts for this specific twin-circuit, can you take a look, please, if it fits?

    1N4148 DO-35 switching signal Doide
    2SC1740 C1740
    A1015 2SA1015 0.15A/50V PNP TO-92 DIP
    Panasonic FM Series Capacitor Low Impedance (25v, 220uf)

I haven't done my homework regarding the resistors yet, can you suggest what kind suits best here?

Author:  infiniteneslives [ Sat Apr 29, 2017 12:05 pm ]
Post subject:  Re: Correct Famicom AV mod

ThePunisher wrote:
I haven't done my homework regarding the resistors yet, can you suggest what kind suits best here?


Your selections look fine to me at a glance. There's nothing special about the resistors.. Just get the suggested values in carbon film and you should be fine.

Author:  ThePunisher [ Sat Apr 29, 2017 12:19 pm ]
Post subject:  Re: Correct Famicom AV mod

infiniteneslives wrote:
ThePunisher wrote:
I haven't done my homework regarding the resistors yet, can you suggest what kind suits best here?


Your selections look fine to me at a glance. There's nothing special about the resistors.. Just get the suggested values in carbon film and you should be fine.

Thanks alot, friend! I will post a video of gameplay, once all the parts arrive, and I'm done with soldering.

Author:  ThePunisher [ Sat Apr 29, 2017 10:19 pm ]
Post subject:  Re: Correct Famicom AV mod

infiniteneslives wrote:
ThePunisher wrote:
I haven't done my homework regarding the resistors yet, can you suggest what kind suits best here?


Your selections look fine to me at a glance. There's nothing special about the resistors.. Just get the suggested values in carbon film and you should be fine.


Btw, the resistor values, described in the screenshot are regular ohm, right? Not kilo- or micro- ?

Author:  infiniteneslives [ Sat Apr 29, 2017 10:42 pm ]
Post subject:  Re: Correct Famicom AV mod

Correct.

Author:  ThePunisher [ Fri May 05, 2017 8:35 am ]
Post subject:  Re: Correct Famicom AV mod

infiniteneslives wrote:
Correct.

Hi, once more I need to consult with you:
    Where did you take the Ground? 80sFreak was very specific about it "Take ground from pin20 PPU. Don't ask why, just do it."
    Did you lift the leg of PPU or just cut the pcb route? I really want to keep PPU untouched.
    What kind of wire did you use? Shielded? Single vein?

Author:  infiniteneslives [ Fri May 05, 2017 9:01 am ]
Post subject:  Re: Correct Famicom AV mod

I wouldn't lift any pins from the PPU if it were my famicom. Maybe it would help remove some of the jail bars if I did though..?

You can see where I took ground in my pictures. I just took it from the most convenient location. You can also see I just used cheapo IDE style ribbon cable.

These choices prob aren't the best ones. They were just what I had and met my desires just fine. Feel free to experiment!

Author:  tepples [ Fri May 05, 2017 9:19 am ]
Post subject:  Re: Correct Famicom AV mod

My speculation about the use of pin 20 in particular:

PPU pins 40 and 20 are the PPU's power and ground pins, connected to the bypass capacitor nearest the PPU. I guess taking ground close to the PPU avoids ground loops and unwanted coupling.

Page 2 of 2 All times are UTC - 7 hours
Powered by phpBB® Forum Software © phpBB Group
http://www.phpbb.com/