I've had a Neoflash 64 mb flash cart since they first came out, and it works perfectly fine in my Japanese Duo R or my US Turbo Express. I recently acquired a Turbografx 16 at long last, but the cart doesn't work on it. The menu comes up, but when you select the game it either freezes immediately, or will play the game with really odd issues, like garbled graphics or simply being in slow motion. I can then take the same card and toss it in my Express and all games work perfectly.
I did some searching, and I found where nat said that the card sometimes has issues with power consumption if the AC adapter wasn't putting out enough juice, and sure enough I was using a Sega AC adapter since I don't have the original TG16 plug. I randomly found a universal AC adapter today that can output up to 12V, 1300 ma, which exceeds that of the original AC adapter. I tried it, and it works fine with the system, but still no luck with the flash cart.
Anyone have any ideas? This isn't a big deal since I can always use the Duo instead, but it's irritating.