Subject:
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RE: External Power Port Problem..?
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Newsgroups:
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lugnet.robotics
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Date:
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Thu, 2 Dec 1999 00:07:19 GMT
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Original-From:
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Tilman Sporkert <tilman@activesw.SAYNOTOSPAMcom>
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Viewed:
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738 times
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Although I didn't see an "Use only Lego approved power supplies with the
external power connector" in the manual, I believe Lego has no obligation to
fix your RCX brick. The connector is for an external AC power pack, not a
custom Lithium Ion DC battery pack. That they replace it for you is a nice
gesture. They won't have this problem with new RCX bricks anymore, as they
don't have an external power connector. If you get one of those, you're
screwed.
I suspect that a diode in the AC input rectifier circuit blew up. Your
Lithium Ion battery pack can probably deliver much higher currents than the
official Lego AC power pack. That can make a difference if you have all
motors at full power and stalled or heavily loaded. And because your battery
pack delivers DC, all the power goes through one pair of diodes. With AC, it
alternates between two pairs, so each diode carries only half the power. If
the diodes aren't dimensioned for this kind of usage, they will get warm,
then hot, and eventually fail. I recall a message with a similar problem on
this list some time ago. If that's the case, then you will be blowing up
your replacement bricks sooner or later, too.
Good luck!
Tilman
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Message is in Reply To:
 | | Re: External Power Port Problem..?
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| (...) I wonder if this is why the power port has disappeard from the Mindstorms 1.5... The suspicion is, that the genuine supply has a relatively high internal resistance, and therefore 'current limits' if a lot is drawn from the motor outputs, (...) (25 years ago, 1-Dec-99, to lugnet.robotics)
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