CRT:RGB Video Modifications
Methods
There are five main methods to add RGB to a set.
Method 1: OSD Switching
This method is probably the most common RGB mod. It is only possible on sets where the Jungle IC has analog RGB inputs for the on-screen display (OSD). Basically, you inject your RGB signals into these pins and wire a physical switch to the blanking pin so that the entire screen is displayed instead of the OSD menu. The switch allows you to "turn off" the mod, so that the OSD menu can still be used.
Method 2: OSD Mux
This method requires a custom circuit that multiplexes (muxes) your RGB signal and the OSD signal together so that both can be used at the same time without having to install a physical switch. It is only possible on sets where the Jungle IC has analog RGB inputs for the on-screen display (OSD).
Method 3: Picture-in-Picture (PIP)
In this method, you inject your RGB signals into the PIP pins so it displays your image instead of the PIP and then wire a physical switch to the blanking pins so that the PIP image fills the entire screen. The switch allows you to "turn off" the mod, so that the PIP feature can still be used if you wanted.
- Some displays may have a setting to make the PIP full screen and therefore not require a physical switch.
Method 4: Unused RGB Input Switching
This method involves using unused RGB input pins on your Jungle IC and a switch wired to a select pin to use them. It is only possible on sets where the Jungle IC has unused analog RGB inputs and a select pin. While some sets this is directly possible, some (if not all) Sony and JVC sets disable the unused signals digitally by setting the RGB SEL register in the Jungle IC which disable the ability to select the unused lines. This can be defeated by intercepting the commands with a microprocessor [1][2][3], but it is a complex modification and may be different for each set.
Method 5: Neckboard Injection
This method is the most primitive and should be a last resort. It involves directly wiring your RGB signals to the neckboard of the CRT. This bypasses all safety circuits and adjustments. In the event that something goes wrong, it has the potential of killing whatever device you have hooked up to it. A safety circuit could be designed to mitigate these risks.
Specific Models
JVC
- JVC H-1950CG and discussion -
- JVC AV-27020 - Doesn’t seem to need resistors or caps on the RGB lines at all.
- JVC AV-32D501 - Modder recommends using LT1675 RGB mux IC to restore OSD. Models AV-27D200, AV-27D201, AV-27D500, AV-27D501 seem very similar.
- JVC 32" D-series and discussion
- JVC TM-1700PN - This one uses SCART, but the back panel can probably be more easily modified for BNCs. Note the chassis is steel, so you will need a proper drill.
Panasonic
- Panasonic CT-32G13W - Possible glitches? Not confirmed if console or not.
RCA
- RCA F32685 - Needs resistors (e.g. 1k trimmer pots) on colour lines.
Samsung
- Samsung CB-564BV “Vision Plus” - Needs amp on colour lines.
Sony
- FV310 series (BA-5D Chassis)
- Sony KV-27S42 and another example - Use S-video’s Luma sync.
- Sony KV-27FS100 (2003) - Use CSYNC instead of over composite to help eliminate interference.
- Sony KV-27FS120 - PCB design in comments.
- Sony PVM 14N5U - Discussion, needs research. Post results.
Toshiba
- Toshiba 20AF41C - Recommended to replace 0.1 µF RGB decoupling caps with higher rating.
- Toshiba 27A30