The problem with this, as I know from experience in dealing with this exact same issue is the firmware in the CGA/EGA/VGA converter board. There is an update that needs to be written to the converter board in order for the POG T340+ boards to work with them, I've had to do the exact same thing. I ordered 40 of the converter boards and then shipped them to a guy in Florida that updated the firmware in all of them to work with my POG T340+ boards. I personally don't have the cables to update the firmware in the converter boards but I think it's done using HyperTerminal in windows.I got some(ALOT) of them Chinese CGA/EGA to VGA converter boards, unfortunately I cant get them to work with what I need. After some googling I see it as a common problem with them is a bad batch of firmware.GBS-8200 styled board. img http://110.imagebam.com/download/hr1RD24Ig3jEPLGUtY7-lQ/36574/365736084/GBS8220%20Ports%20%26%20ICs.jpg Im trying to take the RGBS out of a POG boardimg http://g02.a.alicdn.com/kf/HTB1wZBzJFXXXXceXFXXq6xXFXXXV/A-variety-of-large-game-arcade-computer-boards-POG-T340-Pot-o-Gold-510c-580F-version.jpg After looking through the POG manuals, I don't see any information on its sync, or clamp settings ext.I looked through the GBS-8200 it says there is a i2c isp header for updating the firmware, but no relevant links on where to get it or how to put it on.I think either the settings or wrong, or that the boards don't have working firmware. I bought a couple to see if it was a device problem, but dosent seem to be.Iv tested the POG board using my friends CGA compatible CRT and it comes up just fine. I can get as far as soldering the pins to the I2C interface for updating, but I don't know what the command is nor do I have the firmware.I tried pulling the firmware using my MINIPRO-TL866 programmer, but there docent seem to be a setting for the mtv230mv chip.Also, my OS is linux.UPDATE:After lurking Russian and Arabic hacker forums (And being probably put on several NSA watch-lists for registering on them) I located what i believe to be the firmware. And some program to flash it with. So, Now i need to figure out how to use Postal2 ext.Also, a friend came over and lent me his motherboard with the same chip-set, but different firmware and it worked like a charm. So that proves this can work. I also poped the chip off and used it on my board ant it worked, so its definitely firmware on the MTV230Here is the datasheet for the MTV230 datasheetClarification:How do I write/read the firmware to the MTV230 using its I2C interface?Using a Arduino, or a USB I2C adapter on Linux. 
Knockoff CGA/EGA to vga firmware update
linux;firmware