Wondermega Power

I've recently become a little concerned about the AC adapter I've been using for my Wondermega as it seems to make the area around where it connects get rather hot. The adapter I've been using is apparently a Mega Drive model 2 adapter, Model SA-190A (10V, 850mA) and the one Yakumo indicated as the original adapter is a Model SA-170 (9.5V, 1.5A).

I'm not positive that the SA-170 is actually the original adapter that came with the Wondermega as it says Sega instead of Victor. I'm also a bit confused as Jamtex indicated in this thread that the Wondermega takes 9.5V 1.2A.

In any case, the Mega Drive 2 adapter works and the SA-170 doesn't work at all. I don't know what's wrong with the SA-170, and I have no idea where I could find another one. Could I use another adapter with the same voltage and amperage? I would open the SA-170 just to see what's inside, but it uses some strange proprietary screw for which I have no tool. I can take pictures if necessary. Thoughts?

 

The SA-170 was the PSU that came with the system when I bought it and did work fine however over time he wire became tempremental which I why I switched to the Mega Drive 2 PSU that works fine. I did mention that when I sold you the unit :nod:

If you do open the SA-170, all you'll need to do is solder on a new cable since that's all that's wrong with it. The actual PSU is fine or was fine the last time I used it so I guess it still should be.

From the official Sega Wondermega info page
本体
DC9.5V 1.5A センタープラス
ACアダプター AC100V(50/60Hz) 電取法 甲種（国内向け）

Basically it says,

Hardware
DC 9.5V 1.5Amp Center Line
AC Adaptor input 100Volts 50/60 htz

So as long as you're not putting more than 1.5Amps in to it the system will be fine.

 

Current isn't forced through a device, the device draws what it requires. The higher the current rating of the adapter, the better it will perform. The reason the 850mA adapter is getting hot (warm is normal) is because the transformer inside is being overdrawn by the console, if the console is rated for 1.5A you should use an adapter rated for 1.5A or GREATER. The voltage doesn't terribly matter since it's regulated into 5V. Typically you want exactly 9V, any higher and the regulator is losing efficiency (it's lost as heat).

 

Do you happen to know where I might get the tool needed to open it? It's kind of like a star-shaped bolt. Also, could you give me a link to the official Wondermega site? I wasn't able to find it.

It isn't the adapter I'm worried about; every AC adapter I've ever had gets a little warm after a while. It's the Wondermega itself that gets rather warm/hot (not sure how to make the distinction). Specifically, the area within about a 2 inch radius around the place where the AC adapter is plugged in gets rather warm after use.

In any case, do I need to fix the SA-170 I have, or could I use another adapter with the same voltage and amperage?

 

Does that part really matter that much? I've been using a Japanese Saturn, which is 100V, for years and I've never had any problems with it.

 

Not sure to be honest. I've bought a few odd shapped drivers from electrical store in Japan. The last looking like a star but I'm not sure about online.

It's very hard to find the page from Sega's own site. I'm not even sure they have it linked to any more. Anyway, here it is - http://sega.jp/archive/segahard/mcd/wonder.html

 

Then you need step-down

Anyway and like mentioned in previous posts. The current is given by its Load (Device), the used output voltage and last but not least by the power supplies own limitation (capacity). If the PS can't provide the needed current, it gets overworked, in other words it can't deliver the needed current and the terminal-voltage will drop, so so does its performance.

Take a 9V and I > 1500mA (center line) PS -> nothing can get wrong.

 

Shouldn't it be 9.5V, or is the .5V difference not important? And as far as the voltage coming into the PSU, does it really matter if it's 100V or 120V?

 

Old PSUs were plain coil-transfomers. So they just transforming an alternate voltage (AC) up or down according their primary to secundary coil ratio (number of turns per unit length).

So if you put in 20% more than usually, there will be also 20% more of the expected output.

 

So... would that be a bad thing? And you're referring to the voltage coming out of the wall, right?

 

As in, if you put 20% more voltage into one of these simple power supplies on the wall side (100volts -> 120volts), there will be another 20% on the output end as well.

Technically consoles have voltage regulators to keep put the voltage at what the board inside requires, but that doesn't mean it or the PSU won't be working way harder or differently than designed.

 

wondermega power supply

Believe it or not, the USA Sega CDX power supply has identical output specs as the Wondermega RG-M1 one and the same connector. I've confirmed that it does work.

 

The Wondermega PSU consists of 4 diodes (or a bridge rectifier), a capacitor and a transformer. The two common things that happen is that the PSU is shorted out and burns out a diode or the transformer and more commonly the wire from the PSU to the conncetor gets damaged. if plugging in the transformer you can hear it buzzing then it's probably the wire that is gone, if you get silence then it could be a loose connection from the plug to the transformer.

Back to the original question, I have used Megadrive 1 PSUs rated 9V at 1.2A on the Victor Wondermega RG-M1 with a new connector and have had no issues with them, even using them for 9 hours at a time for the last 8 years. However not all PSUs are built well so if I was going to use a PSU then I would use a switched mode 9V >1.5A PSU as you can get them for 20 pounds from places like maplins.

All megadrives, wondermegas, cdx, mega cds, etc have voltage regulators in the machine so it doesn't matter how accurate the voltage goes into the machine. Most Sega PSUs were marked from 9V to 10V, 9.5V is an average. In Europe, officialy the voltage is 230V but in the UK and Ireland it is 240V and the rest of Europe is 220V but devices generally will work within a tollerance of 10% either side.

So stick in 9 to 10v and any current over 1.5A and you would be fine.

 

12V 2A brick is what I use, works nicely. If you use a low power brick then you'll be getting problems with CD lid opening (my MD2 AC brick was causing problemso n that regard), and old rubber belts are not helping either.

 

12v 2A seems like a bit much. Lots of power getting turned into heat.

I know when I first got my Mk1 Sega CD, I thought it was faulty (and subsequently dismantled and recalibrated the tray position and stuff). Turns out the cheap chinese brick I was using was fucking with it. The tray would open slowly and didn't close all the way half the time, it obviously didn't read discs... Also led me to find out that some of my Genesis consoles worked totally perfectly, and that the PSU was actually at fault. Victoly!

 

Wondermega uses a bit more efficient regulators than 7805, though there will still be a bit more heat... but higher voltage brick allows for bigger voltage drop on heavier load(read disc lid opening).

 

I don't suppose you know where one could get a Sega CDX power supply by itself, do you?

 

i have got these there 9.5V 2.5AMP
works well have tryed these cheap replacement

http://cgi.ebay.co.uk/NEW-9-5V-AC-A...Accessories_PowerSupplies&hash=item3f02c1c80d

 

Sega Parts has had the CDX AC adapter in stock by itself for a while now. I think that Sega manufactured too many spares, after overestimating the demand for the hardware. Not affiliated, just trying to help. Link:

http://www.leftcoastgames.com/produ...id=99&osCsid=5b1767c1177e369468be451325fa5dac