He, pals :)
I redesigned the 2 stage amplifier (for Famicom or other Fami-clone) made by our friend Krzy
https://www.famicomworld.com/forum/index.php?topic=14022.msg180457#msg180457 ;D
This scheme gives the best picture :) it requiters more elements then other schemes out here,but totally wort it :o
So here is my idea
If you like it I am providing the my PCB design :)
I will post pictures from how it works, but first have to get 2 missing caps and add them to the my tiny PCB :-[
The right PCB is my first build , then the idea to direct mounting come to me :)
PCB 2 variants : https://drive.google.com/file/d/1ZlO5pluLLxuw5bIf_H6ZmhJXOK8t6xQ2
PCB "installed" : https://drive.google.com/open?id=1X2Bln9RpctxWEHkeQZd4CPTXuTinxFEi
Scheme by Krzysiobal : https://drive.google.com/open?id=1B2SnWUG0rg1OTvBb7xCDLIaIFeqgjEez
PCB layout : https://drive.google.com/open?id=1rI1I_mKhZBo1SRcr6tbHqdMwib45nsJF
BTW
I can not upload pictures here, because of this I am giving links from google drive.
Admins please do something ??? :help:
Quote from: FAMICOM_87 on December 16, 2018, 08:27:36 am
BTW
I can not upload pictures here, because of this I am giving links from google drive.
Admins please do something ??? :help:
Yeah, apparently we hit the max disk usage that I had set (1gb). I upped it to 2gb, so hopefully will allow attachments again.
Quote from: togemet2 on December 16, 2018, 01:59:11 pm
You can display them by doing the image tag: <img>link here</img>
do not work :(
Quote from: FAMICOM_87 on December 16, 2018, 08:27:36 am
This scheme gives the best picture :) it requiters more elements then other schemes out here,but totally wort it :o
It is only about proper analog ground line around video amplifier.
When video amplifier connected directly to the PPU, it will not collect noise from the ground line across the PCB.
When output of video amplifier connected directly to RCA and only, it will not allow to sneak any noise fron the ground line.
End of story, period...
what is that big difference between NES and Famicom? NES is totally free of jailbars :)
Post Merge: December 18, 2018, 12:17:20 pm
Quote from: FAMICOM_87 on December 17, 2018, 11:14:17 am
what is that big difference between NES and Famicom? NES is totally free of jailbars :)
I make some measurements and discover this :
NES - PPU pin 22 is connected to CPU pin 3 and IC 74HCU04 pin 9.
Famicom - PPU pin 22 and VCC are connected directly and not connected to the CPU pin 3, and there is no 74HCU04 on the famicom boards !
one more think famicom is running on about 4.93V , and the NES is 4.98V
are those differences related to the jailbars issue ?
The Famicom does not reset the PPU when you hit the reset button, that's why the graphics get weird when you hit reset on the Famicom, and not the NES. (pin 22)
I think the NES PCB design has more to do with the reduction in Jailbars.
I tried the NES, AV Famicom and Twin famicom video circuit on a Famicom and still had jailbars, the best thing that works for Jailbars in my experience is lifting the composite video pin.Capacitors help too.
My favorite video circuit is the NES one, the AV Famicom circuit looks too dark on CRTs.