Japan - US Step Down Conversion

[strygo]

I've long used Japanese devices rated for 100V in the United States without any step down transformer. This was mostly due to my ignorance as a teenager (the plugs match!). More recently, I've been careful to track down replacement AC adapters that specifically handle US voltages. This does leave at least a handful of consoles that have internal AC converters (Saturn, Dreamcast, etc.)

In poking around some old threads here as well as elsewhere on the web, the responses to the question 'is it safe to do this?' fall into one of three categories:

* No! Your house is going to catch on fire.
* I've been doing it for years. Don't worry about it.
* It creates extra wear and tear on the console and may reduce the age of components.

There is a separate consideration that I haven't seen answered anywhere (thus the reason for this thread). Has anyone investigated on a console by console basis (this may extend to specific models, I'm not sure), whether specific ones are internally rated for the wider range that spans both Japanese and US voltages? Knowing for example that a system's power supply was internally rated to handle 80V to 130V would imply that a step down conversion is totally unnecessary.

The answer to this may be no, but I have to believe if console designers could reduce permutations a bit, they would have. I also recognize this whole pursuit doesn't help friends in Europe and elsewhere. Apologies if someone has done this analysis and I've missed it!

[Lawfer]

Video game consoles are rated to use 100v-120v.

[strygo]

Lawfer: this very well may be true. Are you aware of any analysis performed that definitively concludes this? My Japanese Saturn, Dreamcast and 3DO all specifically list 100V, whereas their US counterparts list 120V.

[Lawfer]

Lawfer: this very well may be true. Are you aware of any analysis performed that definitively concludes this? My Japanese Saturn, Dreamcast and 3DO all specifically list 100V, whereas their US counterparts list 120V.

Simply because the japanese Saturn was made for the japanese market just like the US Saturn was made for the US market, it really doesn't matter as long as you don't try to feed 220v-240v to your japanese or US saturns.

[andy251203]

As far as basic AC adapters go (the wall warts that consist of a transformer, 2 or 4 diodes and a smoothing capacitor) it won't hurt anything to feed it an extra 20 VAC.

Think about what a transformer does, and how a higher input voltage would affect it.

If you take an AC adapter that is rated for 100VAC input and 9VDC output and give it an input of 120VAC, then logically your output will be around 10.8VDC. Can your Famicom or SNES handle 10.8VDC? Probably. Your 7805 voltage regulator might get a little warmer than usual.

Now if you take that same AC adapter and feed it 240VAC, then your output would be somewhere around 21.6VDC, much too high for your game console. But the AC adapter itself would be unharmed.

[stuntman]

Now if you take that same AC adapter and feed it 240VAC, then your output would be somewhere around 21.6VDC, much too high for your game console. But the AC adapter itself would be unharmed.

Really? Nothing would go pop or overheat?

[strygo]

I'm hoping to figure out definitively whether the variation in voltage is truly in spec or not. I appreciate the attention to detail that folks on this forum bring to various topics. From palettes, to lag times, to TTL voltages, that focus is impressive.

I don't have a background in electrical engineering to know whether the variance described is something the console designers planned for or not. At first blush, a variance of 1-2 VDC seems quite high, especially given the concerns over the summer about the EverDrives.

If anyone with said experience knows what to look for when examining an internal PSU, I'm happy to take a stab at looking at the consoles I have for any clues. I'm selfishly curious (I have two consoles, Saturn and 3DO, that I'd like to know if I'm damaging) but this knowledge seems general purpose enough to benefit the rest of the community.

[bigbadboaz]

I have seen posts in the past from engineering types stating that 120v vs. 100 is "within the tolerance" built into internal power supplies in consoles like Saturn, PS1, etc. Take that as the hearsay from a non-engineer that it is.

That said, your original post reads like you want a solution for those consoles more than you want an intellectual exercise, since you have bought replacement AC adapters wherever possible. Are you aware that you can buy step-down converters for this purpose? You basically get a little brick that you plug your console into, and it ends up looking like it has a wall-wart AC adapter like all the rest. The converter supposedly outputs the 100v you really want. I had your same concern from day one when importing a PS.. these little devices were always available and not expensive.

FYI.

[viletim]

I have seen posts in the past from engineering types stating that 120v vs. 100 is "within the tolerance" built into internal power supplies in consoles like Saturn, PS1, etc. Take that as the hearsay from a non-engineer that it is.

Normal line tolerance is usually 5-6%. I really wouldn't exceed 10%, especially on older equipment. Now it is common to find 100-240V switching power supplies, but this was not the case in the 1990s.

[strygo]

That said, your original post reads like you want a solution for those consoles more than you want an intellectual exercise, since you have bought replacement AC adapters wherever possible. Are you aware that you can buy step-down converters for this purpose? You basically get a little brick that you plug your console into, and it ends up looking like it has a wall-wart AC adapter like all the rest. The converter supposedly outputs the 100v you really want. I had your same concern from day one when importing a PS.. these little devices were always available and not expensive.

Yeah, I will plan to pick up a converter or two if I can't turn up anything. The whole topic is a curiosity to me given the wide gamut of answers on whether it is safe or not.

Normal line tolerance is usually 5-6%. I really wouldn't exceed 10%, especially on older equipment. Now it is common to find 100-240V switching power supplies, but this was not the case in the 1990s.

Was there a specific technical innovation that enabled this change?

[Lawfer]

(I have two consoles, Saturn and 3DO, that I'd like to know if I'm damaging)

You're not, as long as you don't feed them something that is much higher than 120v, what might damage them is voltage spike after a blackout when the electricity is restored.

[viletim]

Normal line tolerance is usually 5-6%. I really wouldn't exceed 10%, especially on older equipment. Now it is common to find 100-240V switching power supplies, but this was not the case in the 1990s.

Was there a specific technical innovation that enabled this change?

There have been lots of improvements in low cost switching power tech. since the '90s. Especially in the semiconductors/controller ICs.

[gray117]

It's fine. Well within general tolerance.

If you were looking at something that was 24/7 uptime you'd be of course looking at tuning this and back ups. But you're not a data center and in fact turning on and off also causes some wear so there's no real reason to be worrying about this one way or another ... all of this set against age + previous use ... longevity in general use really starts coming more down to luck

[Unless there's an identifiable period/product line from where there's known to be sub par components... or just end of life period... ]

Switching supplies became more common since it enables rapid production of flexible stock (particularly in smaller low power devices) without changing manufacturing lines, or - in the worst case - dumping unsold stock from a particular region, whilst making more for another region. You'll often see most consoles at least have a modular internal design to accomodate different power blocks. Amongst higher power devices it can be more economic (sometimes just size too) to just have this switch as a manual switch (often the case on pc power supplies for example), or with a different external transformer/power brick, rather than having a truely automatic switch... In either case, more of change as a result of general marketplace/stock/manufacturing practices than 'technology'.

[rama]

Now if you take that same AC adapter and feed it 240VAC, then your output would be somewhere around 21.6VDC, much too high for your game console. But the AC adapter itself would be unharmed.

Really? Nothing would go pop or overheat?

Switching supplies in a Playstation or Sega Saturn have region specific components on the primary / high voltage side.
A Japanese PSX for example uses a big storage capacitor of 100uF / 200V. The highest voltage applied to it is a function of the AC voltage in the country.
Typically, this capacitor has to be able to tolerate about double that nominal AC voltage.
In a PAL PSX, this capacitor is rated for 400V.

If I were to connect my countries ~230V to a Japanese console, this capacitor would blow in seconds.
The primary side of the power supply would be damaged, fuses blown, all that. But I assume the secondary and the console itself would be fine.
Anyway, this is apparently a very common failure of power supplies

So yeah, the entire switching power supply design needs to be considered.
This can get complicated quickly, so I would just get a stepdown converter and be done with it.

[Ripthorn]

All japanese SEGA Saturns and Dreamcasts I opened had 130V power supply, some came with 250V 10A dual voltage even saying 100V on the sticker
Probably is the same thing for any console manufactured in the 1990s. In the end I would not bother with this 100-120v thing at all.

[Lawfer]

In the end I would not bother with this 100-120v thing at all.

Exactly.

[rama]

I don't know.. It's too close to marginal for comfort.
The input capacitor sees Vac * sqrt(2) Volts. Nominal 120*sqrt(2) = 170V.
A PSX cap is rated for 200V.

If the component has aged (it has!) and the AC voltage is higher that day.. Just get the transformer

[Syntax]

My Sega MD 1 psu is a linear 10v supply.
Depending on the voltage supplied to my house i have measured it at 14.3v max.
The internal step down can only handle 15v.
This is why they leave around 30% headroom, In case of scenarios like mine.

It's your call.