Sega Genesis Model 1 and Sega Cd systems power supplies question?

[ooXxXoo]

I've been collecting video game systems for the past few years,But I have a question that hasn't found the proper answer yet.I own at least 11 Original Sega A/C Power adapters regarding the Genesis Model 1 and Sega CD systems(the first kind,larger block type)..
http://usera.imagecave.com/capcom2000/HPIM4989.JPG
I know for a fact that they all are compatible with each other regardless,but thats not my point.I'm triyng to figure out what supply came orginally with each Sega System and why Sega decided to add more juice to some of them.
My confusion begun when looking at the bottom of the consoles(Genesis/CD systems) and they all seem to be power rated labeled at 9V 1.2A
This is a comparison in some of the Sega Power supplies power ratings I've encounter with:120V 60Hz 17W 9V 1.2A,***120V 60Hz 20W 9V 1.2A,***120V 60Hz 35W 9V 1.2A,***120V 60Hz 18W 10V 1.2A,***120V 60Hz 20W 10V 1.2
Do you see what I mean?...Where did it go from 9V 17W to 35W and then from 9V to 10V
Do the Sega Cd systems need more juice even tough they are still rated at 9.5V 1.2A on the label?..
None of this consoles are rated marked as 10V 1.2A
Can anyone share some light?

[evildragon]

Reliability...

The voltage regular inside will still down it to 5v, but the more voltage, the more reliable that will be.

[ooXxXoo]

Good try evildragon!...But still not the right answer...You are still full of knowledge!

[evildragon]

You obviously don't know the answer, as you wouldn't be asking.

But it is true, feeding the regulators more voltage makes a far reliable use out of them. They have a minimum and a maximum, depending on their load internally.

[ooXxXoo]

I have at least 3 revisions of the Sega Genesis Model 1 System.The oldest one,has 2 IC's Power Regulators running the motherboard and the newest has only one.So,you are trying to say that Sega used 9V 1.2A to run 2 regulators and used 10V 1.2A to run the latest revision with only one regulator?...What about the Sega CD's systems?...It seems to me that they will be needing more juice,specially the Sega CD version 1 with the sliding door drive,but it is still labeled at 9V 1.2A....Don't quite get it!

[evildragon]

those two regulators were used in parallel... that makes up usually for the weaker supply... not to mention, they may have later realized the genesis needed more power, due to Virtua Racing having it's own CPU which does take power from the main supply.

the motor doesn't take much to open the tray.

[ooXxXoo]

It is just awkward that Sega didn't mention anything like"to be use with 10V 1.2A A/C adapter only"in their systems manuals.And still,all of the Genesis 1 and Sega CD's systems are crearly labeled Rating:9V 1.2A at the bottom of their shells and yet,they were packed with a 10V 1.2A supply.....
Do the Sega System manuals imply anything about the Power Supplies models,like to be use with Model-1602,Model 1602-1 or 1602-3?

[evildragon]

Nope.

It doesn't hurt to use higher voltage, that's the point of the voltage regulator. It only adds to reliability.

(For example, if you feed something like 6-7v, the YM2612 buzzes.. Even though the YM2612 and everything else use 5v)

[ooXxXoo]

I've done some testing with the different original Sega power rate supplies and When a Genesis is running with a higher Voltage adapter,the regulator produces more heat,therefore the console gets really hot and this will affect other components in the long run.It'll be good to know which rating is the most safe and reliable at the same time.

[evildragon]

Of course it generates more heat. The heat is from unused current.

It still ensures a reliable operation though (IE, never running out of current).

Ask any electronics engineer. They'll tell you.

[ooXxXoo]

Exactly...
That's my point...if you are to use the power supply with the Less current power....you might ending needing some more later on...And if you are using the adapter with the most juice,it'll probably affect other electronic parts with heat,specially in those hot summer days after some long periods of game play.
That is why each Genesis revision came with their respective particular Power supply to acomodate their respective needs.

[evildragon]

Except as the Genesis got older, it needed less and less current by itself. The MC68000 was after all, changed to the energy saving model (surface mounted version, late model 1's did have this). This MC68000 drastically required much less, and has one regulator and a puny heat sink.

I believe it was VR, that made the design change, or possibly other 3rd party peripherals that drew from the main supply.

[ooXxXoo]

So according to the Power supplies ratings described from me above ,which one do you suggest to be the most susitable and could have been the one included with the latest Genesis revision with the new energy saving MC68000 and only one power regulator when new?

[ooXxXoo]

I think they just went cheap on us,and tried to save by removing as many parts as possible when other parts where available.Even the Yamaha YM2612 is gone from the last Genesis revisions.I always read about people complaining by the sound of some Genesis output.

[evildragon]

I would reccomend the less rated one for the late MD1 that has the square surface mounted 68K. It doesn't need so much power.

On the other hand, the dual regulator models need as much power as they can get. I think they pull about 800mA when running VR. (or 880mA. I tested this once)

Technically the models without the YM2612 can sound even better than the ones with the real chip. They need a mod to the mixing circuitry though.

http://board.kohina.net/viewtopic.php?p=5808&sid=cf68cd5049de02ca78aa604b270304e4

[ooXxXoo]

Yes,I've done this mod before.But other people is not so technical.

Its weird!...The other day I was working in a Genesis Model 2 and that particular revision had a YM2612

[evildragon]

Pictures?

I don't believe this. No model 2 had a discrete YM2612.

[ooXxXoo]

Check it out!
http://usera.imagecave.com/capcom2000/HPIM4995.JPG
on that picture the Yamaha YM2612 is located at the bottom right corner(front view)near to the reset button,clock and close to the Expansion port.

http://usera.imagecave.com/capcom2000/HPIM5003.JPG
http://usera.imagecave.com/capcom2000/HPIM5004.JPG
http://usera.imagecave.com/capcom2000/HPIM5014.JPG
http://usera.imagecave.com/capcom2000/HPIM5026.JPG

I have two boards like this one,the only difference between them is the encoder.One has the Sony CXA1645 encoder and the other a SKA*** one,but both have a YM2612 chip

[ooXxXoo]

The video output is clear on these boards,because the audio signals are not all mixed up,so there is a lot less noise.

[evildragon]

Keep that machine. It's very interesting, and has forced me to update my Genny database.

I wonder what "CMK" means under the SEGA logo.

[ooXxXoo]

I've always wonder that myself.That CMK logo can be found in other MD2 boards as well.

[evildragon]

Not on any of mine.

[ooXxXoo]

Actually,I've usually seen the CMK logo either right under the game cartridge slot port or above it in other boards,but never in the corner like this one.Also,notice how the hardware to run the Master System converter II was re-located near the heatsink,and now the YM2612 is taking that space on this particular revision.

[evildragon]

The genesis needs no extra hardware for Master System games.

It has a Z80 built in, including Z80 RAM. Genesis games use the Z80 CPU for sound/music also.

[ooXxXoo]

I'm not saying that it does,only that the Z80 cpu was relocated near the regulator heatsink totally to the oposite side where it usually can be found on the board because of the YM2612 chip.

[ooXxXoo]

still,not a clear answer.You are contradicting yourself a bit again,just like with the JROK component board description....By saying above about the Genesis revision with the 2 power regulators..:"Those two power regulators where used in parallel...That makes up usually for the weaker power supply"...and later on replying "On the other hand,the dual regulator models need as much power as they can get"...by indicating that they should used a power supply with more juice...People must be getting even more confused.

[evildragon]

Ok, your trolling now, and frankly, it's pissing me off.

I never contradicted myself. SEGA themselves changed their minds and needed a stronger supply for VR, and possibly any other attachment they design. Even though model 1's got leniant on the supply later on, since it's the same adapter, the same stock used as "replacements" were also used for the new consoles.

As for the parallel regulators, that was merely a mistake on my part. Parallel regulators doubles the output current from the regulators.

As for JROK, when I called you out on that demanding a link to said comment I supposedly made, you never replied.

I rather not get banned from this forum, by feeding your trolling, so you can "research" your answer on Google.

Good day sir.

[ooXxXoo]

No need to argue.

[bones11]

Man, why don't you two just get on the phone and talk? This is like reading a private conversion, you're freaking me out!