Dek's RGB to Component Transcoder (17/5/2020) - This schematic and PCB has been designed to convert a video signal from RGB format to Component (Y,Y-r, Y-b) format. This signal is typically used for retro video game consoles and arcade boards.
You can find the public github here: https://github.com/dekkit/RGB-to-Component-Transcoder
Background Component video can be found in modern CRT TVs to support better picture quality from DVD players and Set Top / Cables boxes. It is found on many later model CRTs and LCD screens.
NOTE - This schematic will not upscale a 240p signal. Many LCD tvs will not display a 240p picture through Component video in!
This schematic was intended to be used for consumer CRT TVs as another way to support RGB (particulary in arcade setups where crt tubes are getting harder to find/replace). It is designed to be used as an external device (outside of the system) rather used internally.
Includes
Design Note(s)
Materials
Initial successful testing (on version VA01 19/4/2020):
Warning
Please share, clone, improve and share again (pay it forward) - that way we can all benefit. This was based on many designs found on the web using the BA7230 chip and from plenty of own my trials and testing the quality of outputs.
ID | Name | Designator | Footprint | Quantity |
---|---|---|---|---|
1 | LM1881 | U3 | LM1881 | 1 |
2 | THS7374 | U2 | TTSOP-14 | 1 |
3 | 10u | C5 | CAP-D3.0XF1.5 | 1 |
4 | 0.047u | C4 | RAD-0.2 | 1 |
5 | 1u | C12,C14,C13,C11,C8,C7,C6 | RAD-0.2 | 7 |
6 | 0.1u | C1,C2,C3,C9,C10,C15,C16 | RAD-0.2 | 7 |
7 | BA7230LS | U1 | SZIP24 | 1 |
8 | 75 | R2,R3,R8,R1,R9,R10,R13 | AXIAL-0.3 | 7 |
9 | 1k | R4,R7 | AXIAL-0.3 | 2 |
10 | 2M2 | R5,R6 | AXIAL-0.3 | 2 |
11 | 680k | R11 | AXIAL-0.3 | 1 |
12 | 1K2 | R12 | AXIAL-0.3 | 1 |
13 | R_3386P_US | RP1,RP2,RP3 | RES-ADJ-TH_3386P | 3 |
Comments (4)
This seems like a good circuit, but can I modify this circuit. I feel like it is missing some connections.
@valdezramses03 It is designed as an open and accessible base circuit to provide for the many possible use cases and range of connectors out there. If you need a version with specific sockets, feel free to message me directly.
Have you thought about replacing the LM1881 with a sync seperator / rebuilder like the ISL59885? It would compensate for out of spec sync levels, or crappy sync. (Like the Genesis).
@Alterac thanks for highlighting the ISL59885 as have not previously considered. I guess it would also add to the cost of the overall design (ie under ~$1 for lm1881 vs ~$8 ISL59885) but the pay off is improved quality. Will keep in mind.