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			<title>Macintosh IIsi, Macintosh LC: Power Limits & Thermal Shutdown</title><body class="ac-gn-current-support">
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<h1 id="main-title">Macintosh IIsi, Macintosh LC: Power Limits & Thermal Shutdown</h1>
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<div id="intro-container"><div class="truncate"><div class="attr SYMPTOMS"><div class="attr TOPIC"><FONT SIZE=4><BR>
What can you tell me about the Macintosh LC and the Macintosh IIsi<BR>
concerning their power supplies and power ratings for their slots?  At<BR>
what temperature will the thermal shutdown circuits shut down the power<BR>
supply?<BR>
<BR>
</FONT></div></div> <!--  attr Symptom  --></div> <!--  truncate --></div> <!--  intro-container --><div class="clear"> </div>
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  <div class="attr SUMMARY">
The power limit for the NuBus slot in the Macintosh IIsi is 15 watts (the<BR>
same for any Macintosh II NuBus slot).  The power limit for the Direct<BR>
slot in the Macintosh LC is 4 watts.<BR>
<BR>
Both the Macintosh LC and the Macintosh IIsi have a thermal shutdown<BR>
circuit which will shut down the power supply in the event of possible<BR>
overheating from excess power draw.  The maximum operating temperature is<BR>
approximately 105 degrees Farenheit.<BR>
<BR>
The Macintosh LC will cycle off-and-on until the temperature reaches a<BR>
safe operating level (It will make a motorboating sound).  At that point,<BR>
it will resume operation.<BR>
<BR>
In the event of overheating, the Macintosh IIsi acts as if you had chosen<BR>
Shut Down and will let you power up it up again only when the temperature<BR>
drops to a safe level.  Pressing the keyboard Power On key has no effect<BR>
in this condition.  If the Macintosh IIsi power switch is locked on, it<BR>
will behave like the Macintosh LC.<BR>
<BR>
<BR></div>
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<div class="mod-date">Published Date: Feb 18, 2012</div>
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