Why??? Its cheaper and safer to use a step down tranny...
I will have to disagree with you there.
First, let's go with the "safer" portion. Many cheap stepdown (or stepup) transformers are usually not built for many watts. In fact, a lot of the cheap Chinese ones flat out lie on the label. Then, when you try to power something and it can't handle the wattage, you likely have a very good chance of starting a fire. On top of the wattage issue, the AC in different countries modulate at different averages. Hell, the AC in different cities
can modulate different amounts. The cheaper the regulator, the worse its ability to handle those spikes. Which could end up frying whatever you have plugged into it.
As far as being cheaper, that's not true at all if you're experienced with modding. A person who has installed a different PSU in a Dreamcast is likely able to know which end of a soldering iron is hot. If so, you can use just about any standard "wall wart" or even PC power supply that outputs the right voltages at the right amps that the system is looking for. For instance, I bought a borked PS3 with a bad power supply for practically nothing that I run off a PC PSU. And, if the system requires several different voltages, you can get parts to stepup or stepdown the different DC
voltages. Parts that are super cheap (or free if you're into scamming Texas Instruments out of free samples), but still of better quality.
The bit about modifying a rare console, I do somewhat agree with. However, if all your mods are internal (as in, not modifying the external case), and only involve soldering on a few wires, I see no problem with that. After all, it's incredibly simple to just desolder whatever you added, and reattach whatever you originally removed. This is assuming you have at least a basic knowledge of soldering and can solder without being incredibly messy. I would not suggest this as a first-time soldering project and possibly killing a 3DO, for sure.
But sure, the most simple solution for all this is to buy a high quality AC stepdown/stepup regulator. It's also the most expensive. If you're going to get one, look at reviews and get a high quality one.
Ok, long reply coming up because i think there are a few points that may need clear explanation here. Dont take offence to anything written or how it is conveyed in text, as it is not meant to offend or upset anyone. It is merely an FYI, and will hopefully be of some help to you. If you have any questions im more than happy to help where i can.
Im a licensed electrician, so essentially youre telling me nothing when it comes to electrical safety. 2 decades industry experience in both domestic and commercial.
The transformer in question is an iron core type, and hence, frequency of supply makes no difference in this country, as i have NEVER seen in deviate any more than 0.4Hz in all my years of testing. You probably wont either, because it is very stable.
There is no regulator involved with a 230v-100v iron core stepdown transformer. Its two lengths of copper wire wrapped around iron laminate. Output is governed by input at the given ratio dictated by the number of turns on both primary and secondary windings.
In Australia, the nominal standard mains power supply is 230 volts for single phase to neutral, and 400volts for phase to phase ( active to active of any 2 phases ) The tollerance is +10% to -6%, meaning the upper most voltage delivered to the point of entry to your premeses is 253volts. Its very unlikely youll see it higher, and without a licence you are not legally able to test the voltage of mains supply, as that is considered unlicensed electrical testing.
Cheap multimeters typically read inaccurately, especially on AC where the RMS value is calculated by cheap components that arent worth a damn. The fact is, the peak voltage at the top of the cycle is well over 300 volts.
The soldering iron comment is a mute point. No soldering is required. Its a straight swap and connects with a ribbon cable. But as i said, the console powered up but would not operate. The fact is you need to find and purchase an FZ-10-E to butcher for it's power supply, only to find that it may or may not operate correctly, if at all. No soldering or console modding experience is going to fix that. This is not a Sega Dreamcast. Theyre all built very much the same, with the power supply being extremely simular. The 3DO is not quite like that. But by all means, try your luck, it may just work, but if it doesnt, where are you then? If indeed there is some sort of issue that damages your console, where does that leave you? Not worth the risk, even if it is unlikely.
The rarity of the console and modding it are quite irrelevant, theyre unlikely to ever be worth considerably more just because theyre bone stock. RGB modding is one perfect example. Im all for modding to improve, but this is not that.
I dont need to do any further research than i allready have. From what you have posted, i think you seem to be assuming that step down transformer works like a phone charger or laptop power supply, which it does not. Its totally different. One is electronic and prone to failure, the other works on mutual induction and is extremely reliable. I do infact still have the Chinese made 230v-100v step down tranny that came with my 3DO way back in the 90s, and it still works perfectly. As it should, because its just two bits of copper wire wrapped around an iron laminate. Not much opportunity for failure.
For that product to be sold in Australia, it must meet certain design requirements. One of those will be that it must use an outer casing that will not burn, if metal it must be earthed, and if plastic it must be self extinguishing. If the electrical installation of your home in Australia complies with AS/NZ 3000/2007 with regard to circuit protective devices and circuit design, a failing iron core transformer will indeed trip the circuit protective device long before it catches fire, and i would be very confident the iron laminate will be earthed, which means even a very minor insulation break down will trip the RCD before the outer case even gets hot. By this point the tranny will have stopped working, and youll be searching for another one or a licensed person that is qualified to test and certify it as safe to use.
If i didnt believe the item i suggested you purchase was safe for you to use, i wouldnt have pointed you in that direction.
The question about wattage is not really worth a thought, as it only applies to a straight up resistive load when in an AC circuit. Output ratings should be listed in VA, as this takes into account inductive and capacitive loads, but most people have no idea what VA is, so they generally throw on a wattage based on a load with a power factor of 0.85-0.9. They rated it at 50w constant, which is 5 times what you need anyway. Divide 50w by 0.9 and you get a better idea of what it can probably do. Mine from the 90s is rated 30 VA. In a resistive load, 1 VA is equal to 1 watt. Inductive and capacitive loads have a power factor that needs to be taken into consideration, and requires reasonably decent equipment to measure. Domestic grade 'energy smart' plug in meters will not measure it accurately, and merely take the V x I approach, why would they care if its accurate, youll never know anyway.
At some point toward the end of your post you mension 'right voltages, right amps'. When it comes to right voltages, on the logic side, 5v, 3.3v etc, its pretty important. At 100v and being AC, its not critical at all, especially since its feeding a switch mode power supply with a regulated output. 'Right amps' is something that needs to be expanded on. To understand current flow is to know that there is no 'right amps' because current flow, measured in amps, is subject to the load applied to the supply, to keep it simple we will discuss DC, where current flow equals voltage supplied divided by resistance of load. In a DC circuit, that calculation is a constant.
5v supply with 3 ohm load, 5/3=1.66 or so amps
5v supply with 10 ohm load, 5/10=0.5 amps
5v supply with 0.5 ohm load, 5/0.5=10 amps
Because the load is not always a constant, the current flow is not a constant. So having explained that, as long as the current able to be supplied is greater than the demand of the load, there will not be an issue.