Subject: Japanese 100V units on USA 110-120V

From: Cameron Kaiser <[email-masked]>
Date: Sun May 11 19:52:15 2003

A recent dream come true (no, nothing to do with the opposite sex).

I am, or will shortly be, the proud owner of a Tomy Pyuuta, the original
Japanese release that evolved into the American Tomy Tutor. It's traveling
on the high seas from Hokkaido, Japan as we speak.

Anyone out there have experience with how Japanese computers of that era
(early 1980s) tolerate United States mains voltage, since Japanese voltage
is lower (100V)? Any recommendations, cautions, or concerns?

At least it's NTSC!

-- 
----------------------------- personal page: http://www.armory.com/~spectre/ --
 Cameron Kaiser, Point Loma Nazarene University * [email-masked]
-- if (you.canRead(this)) you.canGet(new job(!problem)); -- Seen at JavaOne ---

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From: John Lawson <[email-masked]>
Date: Sun May 11 19:52:20 2003

> is lower (100V)? Any recommendations, cautions, or concerns?

   Also most likely 50 htz.

  Two syllables: Variac.   Little one, 2 amps is more than enough.  It is
quite possible that you'll slowly fry the power transformer - it will
always run hot on USA mains. If you can score a cheap small variac, you
can run it on 90 or 95 volts and it undoubtedly will be happy.

  If it has an external 'brick', then you can substitute that for
something that puts out the voltages the Tomy needs.

  But I'd be *real* leery of running lagacy Japanese linear power supplies
on 117/60 lines.

  Domo arrigato.

John

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From: Cameron Kaiser <[email-masked]>
Date: Sun May 11 19:52:24 2003

> > is lower (100V)? Any recommendations, cautions, or concerns?

I thought that Japanese voltage could be either, something like the
west coast being 60Hz and the east coast being 50Hz (IIRC).

> can run it on 90 or 95 volts and it undoubtedly will be happy.

Hmm, okay. I probably should invest in a Variac anyway. Sources?

-- 
----------------------------- personal page: http://www.armory.com/~spectre/ --
 Cameron Kaiser, Point Loma Nazarene University * [email-masked]
-- Now you see why evil will always win, because good is dumb. -- "Spaceballs"

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From: Tothwolf <[email-masked]>
Date: Sun May 11 19:52:29 2003

On Fri, 9 May 2003, Cameron Kaiser wrote:

> > always run hot on USA mains. If you can score a cheap small variac,
> > you can run it on 90 or 95 volts and it undoubtedly will be happy.
>

The best places I've found are electronics scrap/surplus dealers. Variacs
can be found elsewhere, but the prices are usually higher.

-Toth

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From: "Gary Dean Hildebrand" <[email-masked]>
Date: Sun May 11 19:52:34 2003

> is lower (100V)? Any recommendations, cautions, or concerns?

A variac (ISTR is three syllables) will work, but why can't you get a 
18-20vac transformer and wire it to buck the 120v down to 100v?  I'd think 
that would be simpler, and a whole lot smaller. 

Cameron, you said you were in the market for a variac.  I have a couple for 
sale, but they are 10A, complete with STEEL rack panel.  These would be 
great for any workbench, and good for some current as well.  Drop me a line 
offlist. 

Gary Hildebrand
St. Joseph, MO

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From: [email-masked] (Tony Duell)
Date: Sun May 11 19:53:09 2003

> is lower (100V)? Any recommendations, cautions, or concerns?

It might be OK< but it's quite easy to reduce the US voltage to around 
100V. What you need is a step-down transformer giving about 15V from the 
US mains. The secodnary current rating of this transformer can be quite 
low -- 1A should be easily enough.

Connect it like this : 
             +-----------+
             |           | 
o------------+---)||(----+
                 )||( 15V
                 )||( Secondary
Mains      115V  )||(---------------o
         Primary )||
                 )||              100V
                 )||             Output
                 )||                
o------------+---)||
             |
             +-----------------------o

Conncect up the transformer as shown, but don't connect the output to 
your machine yet. Connect an AC voltmeter to the output. If you get a 
higher voltage out (around 130V) that the mains, then switch off and 
reverse the connections to one (but not both) of the transformer 
windings. When you get around 100V out, you can connect it to the 
Japanese machine.

-tony

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From: [email-masked] (Tony Duell)
Date: Sun May 11 19:53:17 2003

> quite possible that you'll slowly fry the power transformer - it will

Why? A transformer desgined for 50Hz will always be happy on 60Hz mains. 
It's the reverse (using the transformer on a lower frequency than it was 
designed for) that causes problems. In general, you need a larger 
transformer (more iron in the core) for a lower frequency. 

-tony