A Power/AV PCB for Famicom (Japanese NES), drop in replacement for the power supply and adding composite video out (instead of RF).

This is the design from krzysiobal user on https://forums.nesdev.org/viewtopic.php?t=23683. I'm just porting for easier accessibility.

It is compatible with

* first revision Famicom (with a big metal shielded dc/rf pcb, a'ka 5 pin), which has power switch on the 5V rail (SW1 is the switch, SW2 should be closed)

* second revision (with a small dc/rf pcb a'ka 7pin), which has power swtch on 9V rail (SW1 should be closed, SW2 should be OPEN)

*I've made it work with my HVC-CPU-GPM-02, but i had to install some wires, as connection is not one to one.

(just connect JP1/JP2 differently according to the description)

It does not have the gretz's bridge, just a simple schottky diode placed on the DC input to protect against wrong polarization.

Video amp is as in most of famiclones.

And the most important thing - there is a place to solder either

* mini jack A+V connector (this way you don't have to drill any holes in your shell)

or

* Audio RCA + Video RCA where originally two switches were placed (you need to enlarge those holes a little)

BOM:

Power part:

DC-005 5.5mm x 2.1mm DC Power Female Jack Socket Connectors- for power supply (https://www.aliexpress.com/item/1005002530301943.html)

1N4004 diode (1N4001 also works without any problems)

C1: 1000uF, 16V (needs to be higher than 9V)

C2: 100n, 16V (SMD size 0805 imperial)

7805 voltage regulator + Radiator (optional)

C3: 100n (SMD size 0805 imperial)

C4: 470uF 16V, (needs to be higher than 5V)

Video part:

R1: 75R (SMD size 0805 imperial)

T1: BC847 (SMD size SOT-23)

R2: 220R (SMD size 0805 imperial)

R3 75R (SMD size 0805 imperial)

C5: 100n (SMD size 0805 imperial)

3.5MM Audio Jack Connector Through Holes PCB Horizontal 4 Contact 4 Conductor Right Angle (https://vi.aliexpress.com/item/33021730474.html) Please also read the note bellow

OR

2x RCA connector

The board is designed for the original 9V center NEGATIVE power supply.

After the composite upgrade the jail-bars are more pronounced, so this board is probably not for those seeking the perfect crisp output.

I've built the board and it works. One thing to note if you're using a 3.5mm to RCA adapter, the video is on the red connector and the mono sound is on the white one. I'm not sure if this is an issue with the original design or with my selection of connector, but it seemed important to point it out.

Jailbar fix:

https://youtu.be/X2DAvCWvceE?t=3495

Adrian's Digital Basement added a couple of capacitors to the famicom motherboard successfully reducing the jailbars.