Subject:
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Re: Power to RCX
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Newsgroups:
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lugnet.robotics.rcx
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Date:
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Sat, 2 Feb 2002 04:38:00 GMT
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Viewed:
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2882 times
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I investigated this issue a while back an have taken apart all four of
my RCX's (1.0 w. adapter, 1.0 w/o adapter, and 2 2.0's from an RIS1.5
and and RIS2.0). They all have internal voltage regulators.
I've written the number down somewhere on this mess I call a desk and
now I can't find it, but I do recall that it's a National
Semiconductor Part of the 78M05 family IIRC.
Anyway this thing accepts a maximum input of 54V (no kidding) while
providing a regulated 5V output over the full current range of the
device (which isn't great, but it only powers the CPU and related
components, not the motors). You're safe there with any reasonable
wall transformer, but the part that I'm not too sure about is the
Melexis MLX1040B used to interface the CPU to the motors. I wish I had
a schematic to see how this is connected within the various RCX
motherboards. I'm certain the control portion of these chips must be
run from the regulator, but the power portion likely isn't. The only
question is: how much voltage can the motor ports take? I've never
been able to find a data sheet for the MLX1040B to find out. I suspect
though, given that it is intended to drive inductive loads, that it
could withstand considerably higher voltages than 5v, but I've never
dared to try it without more data.
Matthias Jetleb
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Message has 2 Replies:
 | | Re: Power to RCX
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| "Matthias Jetleb" <Jetleb@Netcom.ca> wrote in message news:3c5b6892.134862...net.com... [snip] (...) Check out this timely post: (URL) this is indeed the same part, then it looks like 12V is the max. (Figure 1 of the datasheet is a little confusing, (...) (23 years ago, 2-Feb-02, to lugnet.robotics.rcx)
| | | Re: Power to RCX
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| (...) Sorry, I am little confused. Does it mean that everything LEGO did was REMOVING DC adaptor hole to make difference between 1.0 and 1.5 version ? (talking about RCX hardware) and therefore i can connect my wall AC/DC adaptor directly to that (...) (23 years ago, 11-Feb-02, to lugnet.robotics.rcx)
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Message is in Reply To:
| | Re: Power to RCX
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| Most "wall wart" transformers give about 3-5 volts above what is marked on them. I would not use one of these directly. However, I am currently working on using a 7809 voltage regulator. If you don't know, a voltage regulator is a small electronic (...) (23 years ago, 1-Feb-02, to lugnet.robotics.rcx)
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