This is a video of the problem I am experiencing. At certain parts of games, the video starts to blink. Here was what my cable looked like originally: 75ohm resistors + 220uF caps on RGB wires Composite sync with no cap Colors were fine but that problem I mentioned above occurred. When I first modified my cable: 75ohm resistors + 220uF caps on RGB wires Composite sync with 220uF cap Now the SEGA intro screen with Sonic running across it blinked and didn't display properly. My second modification of the cable: 150ohm resistance in total with NO caps on the RGB wires Composite sync with 220uF cap The SEGA intro screen still had the same problem but now the image was darker and really green. Still had the issue that you could see in the video I posted. So I'm thinking my next step will be to put 150ohms +220uF caps back on the RGB wires and a 220uF cap on the raw sync wire. Thoughts?
maybe you're tv doesn't like the MD sync you should be fine with 75ohm resistors and 220uf caps on the rgb lines as for sync, you could try tapping c sync directly from the chip in the MD and running it through a cap and a resistor to the av port (or ad the cap and resistor to the cable) as per mmmmonkeys guide http://www.mmmonkey.co.uk/console/sega/md-sync.htm also pin 8 and 16 should be getting +5v with a resistor on pin 16 i'd check the grounds also 18 is video ground.
Have you tried other things, like a PS1 game on the PS2? Some HDTVs do not support 240p from component input.
Druid II: No thanks, I want to stick with RGB. Edit: Unless you meant composite sync? My cable was originally wired for composite sync and I had issues as you can see in the video. Lum: I haven't tried that yet. I'll do that ASAP. Synrgy87: What value resistor should be on pin 16? I read that guide that you posted a link for. Just for curiosity's sake, why do you have to tap the c-sync directly from the chip? If I just wired pin 20 on the SCART lead to pin 7 on the DIN 8, why wouldn't that work? If mmmonkey mentioned the reason on his guide, I missed it.
180ohm from memory or something around that value. basically when they were designing the mk1 megadrive/Genesis (im assuming yours is a mk1) they for some reason linked both the c sync and c video pins to c video although don't quote me on that(i could well be wrong and its something else). either way they did something funky with c-video and c-sync so tapping it directly from the chip bypasses any funkyness that's why there's more involved than just wiring pin 20 on scart to pin 7 on the din connector. from memory its cutting a trace that goes to pin 7 then from the pin on chip > cap > resistor > pin 7 this helped me with the issues i was having hooking it up to a GBS8220 converter. but yeah make sure you're grounds and switching pins are sorted before doing that. 5v to pin 8 and then 5v through a 180r resistor to pin 16 heres a link to how to wire up various RGB scart cables for different consoles http://members.optusnet.com.au/eviltim/gamescart/gamescart.htm
So I just tried the Sega Ages Phantasy Star Collection and set the mode to 240p. The video DOES display but my TV still shows 480i. My TV is a KDL40EX500.
The genesis scart cables that are sold on ebay have an amp for the Sync. Maybe this could solve your problem. They often use a remarkable difficult to handle chip named THS7314.
It's small as hell. Works as it's own will. I've used it on my NES and the N64. But try using it on anything else and it will be a pain. If you get a dark picture that only needs a little amp. You add the THS and the colors goes crazy, the sync would sync and so on. You need hours of tweaking to get it right.
I've used it as an RGB amp for my Sega Mark III, Duo-R, TG-16 and someone else's Core Grafx II, and it's worked perfectly every time. Yes, it's a small chip but if you use a SOIC-8 adapter board with it, it becomes a lot easier to work with.
recapping could not hurt, might be a good idea for the original poster to check his MD inside for leaking caps, given his other issues
I've noticed that a lot of model 1 Genesis/MD consoles suffer from dried-out caps so a recapping would be a good idea.
