Re: Can a power supply have too much current?

[Tristan Mumford <xtristan.xmumford@xgmail.xcom>]

William Garber wrote:

> 
> "Alex Freed" <alexf@mirrow.com> wrote in message
> u_udnS6An7XPinvYnZ2dnUVZ_vmqnZ2d@comcast.com">news:u_udnS6An7XPinvYnZ2dnUVZ_vmqnZ2d@comcast.com...
> : "Tristan Mumford" <xtristan.xmumford@xgmail.xcom>
> wrote in message :
> news:45e61141$0$91139$c30e37c6@lon-reader.news.telstra.net...
> : >
> : > Anyway, IIRC the +5v is roughly 15A, the 12v
> : > is roughly 5A. Usually I'm happy about having
> : > more current. However the difference here makes
> : > me more than a little nervous.
> :
> : There are two issues:
> :
> : 1. Some power supplies require a minimum load.
> : In most cases this is not an issue. IIGS will
> : definitely load it enough.
> :
> : 2. If there is a short on the board the damage
> : will be greater with a power supply that does
> : not cut out at say 2 amps but happily burns the
> : traces at 15 amps.
> :
> : And also there is always a chance you miswire
> : the outputs. So if I were you I'd first try to
> : find an old-fashioned transformer to get 110V.
> : In fact if you have ANY large enough power
> : transformer it will likely have a split primary.
> : Easy to get 110V.
> 
> International Voltage Converters are cheap, and useful.
> I bought the second one down for a friend in Australia
> who is getting an Apple IIc+ from me.
> 
>
http://www.voltage-converter-transformers.com/light-duty-voltage-converter.html

Thanks for that link. Is that a known good retailer? Ie have people bought
from it successfully? Call me paranoid but I'm still scared of online
businesses.

I have this little thing gnawing away in the back of my mind though about
that site. Maybe two years ago, maybe less we did a lot of research and
scouring the internet and stored looking for something less expensive than
those silly low wattage plugpack stepdowns here for $50.
Every site we found, and every eBay seller selling them cheap were US
postage only.
If that is still the case I wonder if some nice person would be willing to
act as an intermediary. No hurry though. Still in catching up mode from the
expense hit of all the recent necessary travelling.

If I can get my mitts on another cheap AT, ATX etc powersupply I could make
another external supply like the one for my //e ( I still want to add a
soft-on/off ability to that ). But the IIgs is so small and neat. I don't
want to compromise it. I didn't want to with the //e either but it was
killing me not having it working.
The 90 watt Mini-ATX does it nicely. And if I ever get the clone working
it's getting the same fitted internally, given it's ample case.

Anyway, now I have the IIgs my main goal after playing with it for a while
is to use it for prototyping my online idea. It'll even fit nicely in the
dead corner next to the PC. I'll still have the lack of serial port problem
though unless USB serial ports are cheap on eBay these days.

Back to the power. It's killing me having this nice thing which I have
sought after since maybe '93 or '94 sitting on the table doing nothing.

Still on topic I believe. Is there a way of providing a load to a supply
without connecting it to "real" electronics like a computer? And if so how
many voltages need to be loaded to stabilise it? Just the one?
It's just I have a few supplies, all XT unfortunately, that were stored for
aeons with the dead clone. I want to be able to check them with the only
maximum potential fatality being a few cm of fusewire in the house.

Tristan.

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