"I seem to remember a circuit in this forum that was just resistors and diodes, and a refinement adding one IC for the "brown fix." Am I mistaken"
Not mistaken but the quality from that circuit is much lower than true logic solutions. You get washed out colours and colour bleed etc. My solution turns the digital input into a digital output that is then put through a standard DAC, this results in no crosstalk between the colour channels from sharing the intensity signal.
Just a note, I have ordered new boards for my video adaptor that has an S-Video out from the VDC as well as RGB. No idea when they will arrive but I should have them in the store shortly after. to clarify, instead of passthrough for the 40 col output the board now has ALL VDC outputs at RGB and S-Video. It still has audio input passthrough.
In Europe that is the case. It turns out most of the Americans have S-Video in and not RGB, so they have been calling for such an adapter.
I agree about HDMI however the chips to do that are horribad. I need to look at learning VHDL and making a small FPGA converter that can encode the HDMI directly from the CGA input. In theory it's not hard at all but in practice I know nothing about FPGA design.
Hmm. It does sound like the cga2rgb part is fried, which isn't surprising if you reverse voltaged it several times.
It might be worth getting hold of somebody who knows a bit more about electronics to test it for you, maybe somebody who has a working setup and could verify if it's dead. I am sure posting it off wouldn't cost much. Short of that you probably need to buy a new one. I can't hock my own product here as it's out of stock pending arrival of parts, but at least when it's back in stock it has the 5v line clearly marked as well as a removable chip should it get blown up.
It might be worth looking for the cheap resistor based solutions. Maybe somebody could knock one up for you, it's no where near as good but at least you would have a picture.
the VDC doesn't really have PAL/NTSC as that is to do with the colour encoding mainly which it doesn't do. You can swap the number of lines and 50/60hz etc but it's not changing PAL/NTSC as they just don't apply to the VDC.