Cables

16 way (12 bit extender) or 12 way (RGBtoHDMI main board) IDC header to TTL computer connections

Note: 3 bit RGB TTL computers like the BBC micro, Oric/Atmos, QL or Camputers Lynx can also be connected via the 6 way IDC on the analog board or 3 bit TTL buffer board. (See below)
For connections using the 10 way header on the old 6 bit design visit here: old 6 bit connections

BBC micro / Master 128 / Electron (3 bit RGB TTL)

12 Bit Extender 16 way IDC	RGBtoHDMI 12 way IDC	6 way DIN	Notes
Pin 1 green0
Pin 2 red0
Pin 3 blue0
Pin 4 green1
Pin 5 red1	Pin 1 red1
Pin 6 blue1	Pin 2 blue 1
Pin 7 GND	Pin 3 GND	Pin 5
Pin 8 green2	Pin 4 green2
Pin 9 red2	Pin 5 red2
Pin 10 blue2	Pin 6 blue2
Pin 11 RED3	Pin 7 RED3	Pin 1
Pin 12 HSYNC	Pin 8 HSYNC	Pin 4
Pin 13 GREEN3	Pin 9 GREEN3	Pin 2
Pin 14 VSYNC	Pin 10 VSYNC
Pin 15 BLUE3	Pin 11 BLUE3	Pin 3
Pin 16 +5V	Pin 12 +5V	Pin 6	Leave unconnected if powering Pi externally

Oric 1 / Atmos (3 bit RGB TTL)

12 Bit Extender 16 way IDC	RGBtoHDMI 12 way IDC	5 way 180° DIN	Notes
Pin 1 green0
Pin 2 red0
Pin 3 blue0
Pin 4 green1
Pin 5 red1	Pin 1 red1
Pin 6 blue1	Pin 2 blue 1
Pin 7 GND	Pin 3 GND	Pin 5
Pin 8 green2	Pin 4 green2
Pin 9 red2	Pin 5 red2
Pin 10 blue2	Pin 6 blue2
Pin 11 RED3	Pin 7 RED3	Pin 1
Pin 12 HSYNC	Pin 8 HSYNC	Pin 4
Pin 13 GREEN3	Pin 9 GREEN3	Pin 2
Pin 14 VSYNC	Pin 10 VSYNC
Pin 15 BLUE3	Pin 11 BLUE3	Pin 3
Pin 16 +5V	Pin 12 +5V

Camputers Lynx (3 bit RGB TTL)

12 Bit Extender 16 way IDC	RGBtoHDMI 12 way IDC	5 way 240° DIN	Notes
Pin 1 green0
Pin 2 red0
Pin 3 blue0
Pin 4 green1
Pin 5 red1	Pin 1 red1
Pin 6 blue1	Pin 2 blue 1
Pin 7 GND	Pin 3 GND	Shield	Must be connected to both shield halves
Pin 8 green2	Pin 4 green2
Pin 9 red2	Pin 5 red2
Pin 10 blue2	Pin 6 blue2
Pin 11 RED3	Pin 7 RED3	Pin 5
Pin 12 HSYNC	Pin 8 HSYNC	Pin 1
Pin 13 GREEN3	Pin 9 GREEN3	Pin 4
Pin 14 VSYNC	Pin 10 VSYNC
Pin 15 BLUE3	Pin 11 BLUE3	Pin 2
Pin 16 +5V	Pin 12 +5V

Note the 5 way 240° DIN has different pin numbering to the 5 way 180° DIN

Sinclair QL (3 bit RGB TTL)

12 Bit Extender 16 way IDC	RGBtoHDMI 12 way IDC	8 way DIN	Notes
Pin 1 green0
Pin 2 red0
Pin 3 blue0
Pin 4 green1
Pin 5 red1	Pin 1 red1
Pin 6 blue1	Pin 2 blue 1
Pin 7 GND	Pin 3 GND	Pin 2
Pin 8 green2	Pin 4 green2
Pin 9 red2	Pin 5 red2
Pin 10 blue2	Pin 6 blue2
Pin 11 RED3	Pin 7 RED3	Pin 7
Pin 12 HSYNC	Pin 8 HSYNC	Pin 4
Pin 13 GREEN3	Pin 9 GREEN3	Pin 6
Pin 14 VSYNC	Pin 10 VSYNC
Pin 15 BLUE3	Pin 11 BLUE3	Pin 8
Pin 16 +5V	Pin 12 +5V

Spectrum 128 or +2 (4 bit RGBI TTL)

12 Bit Extender 16 way IDC	RGBtoHDMI 12 way IDC	8 way DIN	Notes
Pin 1 green0
Pin 2 red0
Pin 3 blue0
Pin 4 green1
Pin 5 red1	Pin 1 red1
Pin 6 blue1	Pin 2 blue 1
Pin 7 GND	Pin 3 GND	Pin 2
Pin 8 green2	Pin 4 green2	Pin 3	Intensity
Pin 9 red2	Pin 5 red2
Pin 10 blue2	Pin 6 blue2
Pin 11 RED3	Pin 7 RED3	Pin 7
Pin 12 HSYNC	Pin 8 HSYNC	Pin 4
Pin 13 GREEN3	Pin 9 GREEN3	Pin 6
Pin 14 VSYNC	Pin 10 VSYNC
Pin 15 BLUE3	Pin 11 BLUE3	Pin 8
Pin 16 +5V	Pin 12 +5V

IBM PC MDA, CGA, EGA (2, 4 or 6 bit TTL) / Olivetti Prodest PC1 (4 bit RGBI TTL) / Commodore 128 80 column (4 bit RGBI TTL)

12 Bit Extender 16 way IDC	RGBtoHDMI 12 way IDC	9 way D-Type	Notes
Pin 1 green0
Pin 2 red0
Pin 3 blue0
Pin 4 green1
Pin 5 red1	Pin 1 red1
Pin 6 blue1	Pin 2 blue 1
Pin 7 GND	Pin 3 GND	Pin 1
Pin 8 green2	Pin 4 green2	Pin 6	Intensity in CGA / MDA
Pin 9 red2	Pin 5 red2	Pin 2
Pin 10 blue2	Pin 6 blue2	Pin 7
Pin 11 RED3	Pin 7 RED3	Pin 3
Pin 12 HSYNC	Pin 8 HSYNC	Pin 8
Pin 13 GREEN3	Pin 9 GREEN3	Pin 4	Video in MDA
Pin 14 VSYNC	Pin 10 VSYNC	Pin 9
Pin 15 BLUE3	Pin 11 BLUE3	Pin 5
Pin 16 +5V	Pin 12 +5V	N/C

Note: You can use a straight through IDC ribbon to a 9 way IDC D type connector connected to ribbon from GND to BLUE3

Sam Coupe (7 bit RrGgBbI TTL)

12 Bit Extender 16 way IDC	RGBtoHDMI 12 way IDC	Euroconnector	Notes
Pin 1 green0
Pin 2 red0
Pin 3 blue0
Pin 4 green1
Pin 5 red1	Pin 1 red1	31A	BRIGHT
Pin 6 blue1	Pin 2 blue 1
Pin 7 GND	Pin 3 GND	32C	0 VOLTS
Pin 8 green2	Pin 4 green2	31C	GREEN0
Pin 9 red2	Pin 5 red2	30A	RED0
Pin 10 blue2	Pin 6 blue2	29A	BLUE0
Pin 11 RED3	Pin 7 RED3	25A	RED1
Pin 12 HSYNC	Pin 8 HSYNC	27A	CSYNC
Pin 13 GREEN3	Pin 9 GREEN3	26A	GREEN1
Pin 14 VSYNC	Pin 10 VSYNC
Pin 15 BLUE3	Pin 11 BLUE3	26C	BLUE1
Pin 16 +5V	Pin 12 +5V	32A	+5V

Apple IIc digital interface (1 + 1 bit TTL)

This is preferred to connecting using the analog composite video interface as the 4 lines of text in mixed text and graphics mode will be displayed without artifacts.

12 Bit Extender 16 way IDC	RGBtoHDMI 12 way IDC	15 way D-Type	Notes
Pin 1 green0
Pin 2 red0
Pin 3 blue0
Pin 4 green1
Pin 5 red1	Pin 1 red1
Pin 6 blue1	Pin 2 blue 1
Pin 7 GND	Pin 3 GND	Pin 13	GND
Pin 8 green2	Pin 4 green2	Pin 10	GR - switches graphics on
Pin 9 red2	Pin 5 red2
Pin 10 blue2	Pin 6 blue2
Pin 11 RED3	Pin 7 RED3
Pin 12 HSYNC	Pin 8 HSYNC	Pin 3	SYNC - Composite sync
Pin 13 GREEN3	Pin 9 GREEN3	Pin 11	SEROUT - TTL inverted video
Pin 14 VSYNC	Pin 10 VSYNC
Pin 15 BLUE3	Pin 11 BLUE3
Pin 16 +5V	Pin 12 +5V	N/C

Apple IIe digital interface internal pickup (1 + 1 bit TTL)

This is preferred to connecting using the analog composite video interface as the 4 lines of text in mixed text and graphics mode will be displayed without artifacts. Connecting this way should also work with the II+ if you pick up the similar signals internally.

12 Bit Extender 16 way IDC	RGBtoHDMI 12 way IDC	Motherboard	Notes
Pin 1 green0
Pin 2 red0
Pin 3 blue0
Pin 4 green1
Pin 5 red1	Pin 1 red1
Pin 6 blue1	Pin 2 blue 1
Pin 7 GND	Pin 3 GND	UF5 166 pin 8	74166 GND
Pin 8 green2	Pin 4 green2	UE5 344-002x pin 2	IOU GR - switches graphics on
Pin 9 red2	Pin 5 red2
Pin 10 blue2	Pin 6 blue2
Pin 11 RED3	Pin 7 RED3
Pin 12 HSYNC	Pin 8 HSYNC	UE5 344-002x pin 39	IOU SYNC - Composite sync
Pin 13 GREEN3	Pin 9 GREEN3	UF5 166 pin 1 or pin 13	74166 SEROUT - TTL inverted video
Pin 14 VSYNC	Pin 10 VSYNC
Pin 15 BLUE3	Pin 11 BLUE3
Pin 16 +5V	Pin 12 +5V	UF5 166 pin 16	74166 +5V leave unconnected if powering Pi externally

Apple IIGS (12 bit RGB TTL)

12 Bit Extender 16 way IDC	Motherboard	Notes
Pin 1 green0	H3 Pin 5
Pin 2 red0	H4 Pin 5
Pin 3 blue0	H2 Pin 5
Pin 4 green1	H3 Pin 4
Pin 5 red1	H4 Pin 4
Pin 6 blue1	H2 Pin 4
Pin 7 GND	H3 Pin 7
Pin 8 green2	H3 Pin 3
Pin 9 red2	H4 Pin 3
Pin 10 blue2	H2 Pin 3
Pin 11 RED3	H4 Pin 2
Pin 12 HSYNC	H1 Pin 3
Pin 13 GREEN3	H3 Pin 2
Pin 14 VSYNC	UF3 Pin 2 (74F86)	Flip 6 Also available on VGC Pin 49 and TP24
Pin 15 BLUE3	H2 Pin 2
Pin 16 +5V	H1 Pin 10	Leave unconnected if powering Pi externally

Atari ST 40 pin shifter (9 bit RGB TTL + mono TTL)

12 Bit Extender 16 way IDC	Motherboard	Notes
Pin 1 green0	Shifter40 pin 26	G0
Pin 2 red0	Shifter40 pin 29	R0
Pin 3 blue0	Shifter40 pin 23	B0
Pin 4 green1	Shifter40 pin 25	G1
Pin 5 red1	Shifter40 pin 28	R1
Pin 6 blue1	Shifter40 pin 22	B1
Pin 7 GND	Shifter40 pin 20
Pin 8 green2	Shifter40 pin 24	G2
Pin 9 red2	Shifter40 pin 27	R2
Pin 10 blue2	Shifter40 pin 21	B2
Pin 11 RED3		N/C
Pin 12 HSYNC	Glue pin 37	Also on modulator connector pin 5
Pin 13 GREEN3	Shifter40 pin 30	MONO
Pin 14 VSYNC	Glue pin 38	Also on modulator connector pin 4
Pin 15 BLUE3	Glue pin 36	BLANK Also on diodes near shifter
Pin 16 +5V	Shifter40 Pin 40	Leave unconnected if powering Pi externally

Atari STE 84 pin shifter (12 bit RGB TTL + mono TTL)

12 Bit Extender 16 way IDC	Motherboard	Notes
Pin 1 green0	Shifter84 pin 45	G0
Pin 2 red0	Shifter84 pin 41	R0
Pin 3 blue0	Shifter84 pin 49	B0
Pin 4 green1	Shifter84 pin 44	G1
Pin 5 red1	Shifter84 pin 40	R1
Pin 6 blue1	Shifter84 pin 48	B1
Pin 7 GND	Shifter84 pin 74 or 75
Pin 8 green2	Shifter84 pin 43	G2
Pin 9 red2	Shifter84 pin 39	R2
Pin 10 blue2	Shifter84 pin 47	B2
Pin 11 RED3	Shifter84 pin 38	R3
Pin 12 HSYNC	U211C pin 6 (74LS04)	Composite sync: Also on U403 (MC1377) Pin 2
Pin 13 GREEN3	Shifter84 pin 42	G3
Pin 14 VSYNC	Shifter84 pin 50	MONO
Pin 15 BLUE3	Shifter84 pin 46	B3
Pin 16 +5V	Shifter84 Pin 11 or 32	Leave unconnected if powering Pi externally

It is probably easier to solder the RGB lines to the ends of the resistors connected to the shifter

6 way IDC (Analog interface or 3 bit TTL buffer) to computer connections

Note: The TTL computers will also work with the analog interface

BBC micro / Master 128 / Electron (3 bit RGB TTL)

RGBtoHDMI 6 way IDC	6 way DIN	Notes
Pin 1 GND	Pin 5
Pin 2 SYNC	Pin 4
Pin 3 BLUE	Pin 3
Pin 4 GREEN	Pin 2
Pin 5 RED	Pin 1
Pin 6 +5V	Pin 6	Leave unconnected if powering Pi externally

Oric 1 / Atmos (3 bit RGB TTL)

RGBtoHDMI 6 way IDC	5 way 180° DIN	Notes
Pin 1 GND	Pin 5
Pin 2 SYNC	Pin 4
Pin 3 BLUE	Pin 3
Pin 4 GREEN	Pin 2
Pin 5 RED	Pin 1
Pin 6 +5V	N/C

Camputers Lynx (3 bit RGB TTL)

RGBtoHDMI 6 way IDC	5 way 240° DIN	Notes
Pin 1 GND	Shield	Must be connected to both shield halves
Pin 2 SYNC	Pin 1
Pin 3 BLUE	Pin 2
Pin 4 GREEN	Pin 4
Pin 5 RED	Pin 5
Pin 6 +5V	N/C

Note the 5 way 240° DIN has different pin numbering to the 5 way 180° DIN

Sinclair QL (3 bit RGB TTL)

RGBtoHDMI 6 way IDC	8 way DIN	Notes
Pin 1 GND	Pin 2
Pin 2 SYNC	Pin 4
Pin 3 BLUE	Pin 8
Pin 4 GREEN	Pin 6
Pin 5 RED	Pin 7
Pin 6 +5V	N/C

Spectrum +2A or +3 (Analog RGB)

RGBtoHDMI 6 way IDC	8 way DIN	Notes
Pin 1 GND	Pin 2
Pin 2 SYNC	Pin 4
Pin 3 BLUE	Pin 8
Pin 4 GREEN	Pin 6
Pin 5 RED	Pin 7
Pin 6 +5V	N/C

Amstrad CPC (Analog RGB)

RGBtoHDMI 6 way IDC	6 way DIN	Notes
Pin 1 GND	Pin 5
Pin 2 SYNC	Pin 4
Pin 3 BLUE	Pin 3
Pin 4 GREEN	Pin 2
Pin 5 RED	Pin 1
Pin 6 +5V	N/C

Tandy color computer 3 (Analog RGB)

RGBtoHDMI 6 way IDC	10 way IDC	Notes
Pin 1 GND	Pin 1 or 2
Pin 2 SYNC	banded ends of diode pair from Pins 8 & 9
Pin 3 BLUE	Pin 5	Blue
Pin 4 GREEN	Pin 4	Green
Pin 5 RED	Pin 3	Red
Pin 6 +5V	N/C

The RGB connector on the CoCo 3 has separate H & V sync but the analog input expects composite sync so you must diode OR the two sync signals together:
Connect the unbanded ends of two 1N4148 diodes to Pin 8 and Pin 9 of the CoCo RGB connector
Connect the banded ends of both diodes to the Pin 2 SYNC input of RGBtoHDMI

48K Spectrum (Analog YUV)

RGBtoHDMI 6 way IDC	Spectrum Edge Connector	Notes
Pin 1 GND	14B
Pin 2 SYNC	16B	same as Y
Pin 3 U	18B
Pin 4 Y	16B
Pin 5 V	17B
Pin 6 +5V	N/C

Note Some Issue 1 or 2 Boards may require links fitted to bring YUV to the edge connector

Atom (Analog YUV)

RGBtoHDMI 6 way IDC	10 way IDC	Notes
Pin 1 GND	Pin 10
Pin 2 SYNC	Pin 8	HS
Pin 3 U	Pin 7	PB
Pin 4 Y	Pin 9	Video
Pin 5 V	Pin 3	PA
Pin 6 +5V	Pin 2	Leave unconnected if powering Pi externally

Dragon 32 (Analog YUV)

Modifications to create a Dragon external YUV video connector:
Remove the existing 3 pin (5 way) sound and video DIN socket from the power supply board.
Take a 270° 8 way pcb mounting DIN socket and cut off all the solder pins except those equivalent to the ones on the original DIN connector. I used this one:
https://uk.farnell.com/deltron-components/671-0801/din-audio-video-conn-jack-8pos/dp/2989969

Solder this in place of the original DIN on the power supply board.
Connect the following signals to the top of the DIN connector:
6847 Pin 10 (PB) to DIN pin 6
6847 Pin 11 (PA) to DIN pin 7
6847 Pin 17 (+5v) to DIN pin 8
Disconnect one end of R65 to disable the colour subcarrier and give mono video on the video output.

Your original composite cable can still be plugged in after this mod but you have to reconnect R65 to get composite colour

You can now make up the following lead:

RGBtoHDMI 6 way IDC	8 way DIN	Notes
Pin 1 GND	Pin 2
Pin 2 SYNC	Pin 3	Same as Y
Pin 3 U	Pin 6	6847 PIN 10 (PB)
Pin 4 Y	Pin 3	Y
Pin 5 V	Pin 7	6847 PIN 11 (PA)
Pin 6 +5V	Pin 8	Leave unconnected if powering Pi externally but it is preferable to power the Pi from the Dragon

Pick up the sound from DIN pin 1 to feed to an external amplifier.
You will probably also have to adjust RV2 to set the DC level of the video output so that sync tips are at 0V (It won't lock if they are below 0V) After connecting the the converter, adjust RV2 until you get a locked stable image.

Photo of modified Dragon 32: (This picked up +5v from another chip)

PAL Tandy color computer 1/2/MC10 (Analog YUV)

RGBtoHDMI 6 way IDC	Internal Connections	Notes
Pin 1 GND	TCC1000 PIN 1
Pin 2 SYNC	TCC1000 PIN 17	PAL HS
Pin 3 U	6847 PIN 10	PB
Pin 4 Y	TCC1000 PIN 6	PAL Y
Pin 5 V	6847 PIN 11	PA
Pin 6 +5V	6847 PIN 17	Leave unconnected if powering Pi externally

You will also have to pick up the sound internally via a 1K resistor to connect to an external amplifier

It is also recommended that you power the Pi zero externally for better noise immunity but if you are having issues, try both ways. Also powering externally results in instant video after the CoCo is power cycled.

NTSC Tandy color computer 1/2/MC10 (Analog YUV)

RGBtoHDMI 6 way IDC	Internal Connections	Notes
Pin 1 GND	6847 PIN 1
Pin 2 SYNC	6847 PIN 38	HS
Pin 3 U	6847 PIN 10	PB
Pin 4 Y	6847 PIN 28	Y
Pin 5 V	6847 PIN 11	PA
Pin 6 +5V	6847 PIN 17	Leave unconnected if powering Pi externally

You will also have to pick up the sound internally via a 1K resistor to connect to an external amplifier

NOTE:
For the NTSC CoCo 2 you must also remove C59 (150pf) and R9 (1k) as they degrade the video signal. Removing R9 disables the colour artifacting in hires mono mode on the RF output so if you still want that you can try leaving it in if it makes no difference to the RGBtoHDMI picture quality (Both components are not fitted on the NTSC CoCo 1).

For the NTSC MC10 you must remove C33, 150pF

It is also recommended that you power the Pi zero externally for better noise immunity but if you are having issues, try both ways. Also powering externally results in instant video after the CoCo is power cycled.

Apple II / ZX80 / ZX81 / UK101 / Nascom / Superboard II or any other mono computer

RGBtoHDMI 6 way IDC	Phono Connector	Notes
Pin 1 GND	GND
Pin 2 SYNC	GND	Sync is detected on Y
Pin 3 U	GND
Pin 4 Y	VIDEO
Pin 5 V	GND
Pin 6 +5V	N/C

Notes:
The ZX80/81 require a composite video mod.
The PAL encoder on the PAL Apple IIe must be disabled (switch on motherboard) and artifact colour will only work with the manual SW2 switch. (NTSC Apples and PAL Apple II+ will auto detect colour modes)

TRS80 Model 1 (Mono) / Video Genie

RGBtoHDMI 6 way IDC	5 way DIN	Notes
Pin 1 GND	Pin 5
Pin 2 SYNC	Pin 3	Picks up mod sync signal
Pin 3 U	Pin 5	GND
Pin 4 Y	Pin 4	Video
Pin 5 V	Pin 5	GND
Pin 6 +5V	Pin 1	Leave unconnected if powering Pi externally

An unmodified TRS80 will work but you will have to use the auto calibrate occasionally because the composite sync signal is generated by resistor capacitor monostables which drift with temperature.
If you make the following modification, an alternative sync signal which is timed by the crystal can be output on an unused pin of the video connector and then the auto calibration should only need to be done once during initial setup.
Connect pin 1 (HDRV) of Z6 (74C04) to Pin 3 of the 5 way video DIN socket.

Use the "TRS_80" profile for an unmodified machine and "TRS_80_Modified" for one with the modification.

This modification can also be performed on the Video Genie with the HDRV signal being on pin 13 of IC1 in the Sync Gen (Untested)

Photo of mod on a 50Hz (PAL) TRS80 Model 1 Level II:

Commodore 64 (with c0pperdragon's YUV interface)

RGBtoHDMI 6 way IDC	4 pole 3.5mm jack plug	Notes
Pin 1 GND	Body
Pin 2 SYNC	Body (GND)	Sync is detected on Y
Pin 3 U	Ring next to Tip	B-Y
Pin 4 Y	Tip	Y
Pin 5 V	Ring next to Body	R-Y
Pin 6 +5V	N/C

This will only work if c0pperdragon's YUV interface is fitted
See here:
https://github.com/c0pperdragon/C64-Video-Enhancement
Available here:
https://videogameperfection.com/products/commodore-component-video/

The latest 2.7 version of the firmware for c0pperdragon's board has support for RGBtoHDMI built in so if you can update the firmware yourself, you can skip reprogramming the palette below.

Latest 2.7 firmware is here (requires a USB Blaster programmer & software): https://github.com/c0pperdragon/C64-Video-Enhancement/releases

To enable support for RGBtoHDMI on the latest 2.7 firmware, after programming, put a link across pins 9 & 10 of the jtag connector (two pins closest to the back of the case). After that, putting the switch away from the YUV video connector outputs 288p with the special high contrast palette required by RGBtoHDMI so you should use it in that position. To output normal colours use one of the other two positions.

Before link fitted:
Switch towards YUV video connector = 288p
Switch in middle = 576p
Switch away from YUV video connector = 576p with scanlines

After fitting link on pins 9 & 10 on 2.7 firmware:
Switch towards YUV video connector = 288p
Switch in middle = 576p
Switch away from YUV video connector = 288p with high contrast palette for RGBtoHDMI

However it is likely that for the forseeable future the boards from video game perfection will still have older 2.6 firmware so you must follow the procedure below if you are unable to upgrade:

The 3 position switch on the interface should be set to 288p mode (towards the YUV video connector).
After fitting, you must reprogram the YUV interface palette to output a high contrast palette that RGBtoHDMI can discriminate to extract the raw digital pixel data.
This means the analog YUV output will not have 100% correct colours as they will be very saturated but the colours will be correct through RGBtoHDMI

Type the following program into the Commodore 64:

Then RUN it to confirm it outputs the same numbers as below:
(It won't have any effect at this stage)

Finally to reprogram type:
POKE 53311,137
Press Return
Move the interface switch to any other position and back again to signal you want to reprogram
Then type:
RUN
Press Return
Finally type:
POKE 53311,138
Press Return
The interface should now be reprogrammed with the right YUV levels for use with RGBtoHDMI
(This only needs to be done once, the values are saved in the interface)

To restore normal colours so the analog output can be used with an analog monitor, type in this program: