Re: Apple IIgs 110V -> 220V, and VGA adapter?

[mjmahon@aol.com (Michael J. Mahon)]

David Empson wrote:

>MagerValp <MagerValp@cling.gu.se> wrote:
>
>> On a recent trip to the US I picked up a IIgs that I now need to
>> convert so that it'll run off of 220V power, as I live in Europe. I
>> googled a bit, and I find several articles saying that it's a simple
>> jumper switch in the PSU, but none of them have the exact details.
>
>First I've heard of such a jumper.  The IIgs power supplies I've seen
>are labelled externally as either 230V or 110V (I have one of the latter
>- all locally sourced machines have a 230V supply).
>
>I've just opened up one of the 230V models (made by Astec) and there is
>no evidence of any kind of voltage selection - no jumpers or alternative
>connection points for the mains.  The main fuse is rated at 250V, and
>the main capacitor is 400V.  (A friend who knows more about this than I
>do says that if both supply voltages were supported there would be two
>main capacitors.)

Your friend is correct.  The jumper converts the mains portion of the
supply from a simple rectifier (for 230VAC) to a voltage doubler (for
115VAC).  The voltage doubler requires two large capacitors.

>It is possible that the 110V model may be a different design which
>supports being switched to 220V, but I don't have that one handy to
>check.

This is very interesting.  Because all the 115VAC supplies I've seen
were "jumperable" to 230VAC, it never occurred to me that there were
"dedicated" 230v models.  ;-(



-michael

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