Mega Drive I, svideo, 60Hz/50Hz, "too much" colour?

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*Pokes the Mega Drive with a stick*

hmm..

 

sorry I can't really offer any help on the problem but wow! very nice cable work! :

 

Can you explain what's going on in the second picture? The one with the two resistor legs bend towards each other.

I agree with keropi, your wiring looks really nice

 

There's a small IC soldered directly to the CPU pins, an LTC1799.
Its a frequency generator, that you select the frequency output of, by using a resistor.

I had a 10k resistor for 10Mhz, and the other two resistors were in parallel for the 7.6Mhz option, however, a few games still didn't work at 7.6Mhz.

 

not sure how s-video works but it's odd that it's brighter / deeper colour saturation for s-video maybe experiment with some resistors?

 

No, its brighter for 60Hz PAL vs 50Hz PAL.

It has the same effect with composite video too.

 

I'm not sure were are talking about the same. I meant the two thin resistor legs that are soldered onto the CPU and bend very closely towards each other. What's the reason for this? If I'd have to guess I'd say it has something to do with the clock signal, but why did you do it like this?

A bit OT, but I hope it's alright I ask it here. According to this site the Signetics versions of the 68000 can't be overclocked: http://kyorune.com/modding/article.php?id=73
Is that true? I've only done it with the Motorolas which worked fine, but my current MD1 has the Signetics. Not that I ever used the MD in overclocked mode, but it's still kewl to have the option

 

Opps my bad that was a brain slip i meant to say 60/50hz but for some reason put s-video again lol. It was 4am, I was tired.

 

There was an IC soldered between the pins of the CPU... its a frequency generator...
I thought the 7.6Mhz output could be used for "stock" speed, but it didn't work.

 

Oh it's a small IC? That was very hard to see in your picture

 

Can I ask a stupid question? Thoise voltage regulators I've seen you use look fun, but what advantage do they have over a vanilla 7805 regulators?

 

They're a high quality, efficient, switchmode regulator module... plus I got about 50 of them for free
So, they will do 5volts at 2amps, and barely get warm.

If you try to draw 2amps from a single 7805, it'll catch on fire
Even the original power supply in the Mega Drive I, that used two regulators, would get quite warm, even only supplying ~700ma total (from memory)

I'm in Australia, where ambient temperatures could get to 40 degrees Celsius (although air conditioning helps) but I'm still not a fan of the inefficiencies associated with linear regulators.

 

Mmmm... Mega Everdrive...