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Subject: 
Re: External Power Port Problem..?
Newsgroups: 
lugnet.robotics
Date: 
Wed, 1 Dec 1999 23:23:17 GMT
Viewed: 
584 times
  
In lugnet.robotics, "Issac Merkle" <the_gaff@hotmail.com> writes:
Esteemed Colleagues,

I have two RCXs, both of which have stopped responding to power applied
to the external power port. With batteries, they function correctly;
with a 9.6v Lithium Ion battery pack attached to the external port,
nothing. This has not always been the case; in the past, I have
successfully powered my RCXs by an AC adaptor and by the aforementioned
9.6v battery pack. Nothing unusual happened that would have damaged the
units that I am aware of.

Having contacted LEGO support, I am being told that they will generously
replace the RCX units "this time". If any of my RCXs fail in the future
with my having used non-DACTA AC adaptors, they will not replace them.
They feel they "have to draw the line somewhere". The best rationale for
their pushing the blame on me that they have offered is that the
"polarity may have been reversed". My attempts to dismiss that as
nonsense with regard to the AC marking on the RCX have fell on
uneducated ears; I don't think the woman with whom I have been speaking
has a technical bone in her body. I was thinking that someone else had
made some mention of RCX external power port failure. Anyone..?

Does this seem a reasonable response from LEGO? My standpoint is that
the power requirements for the RCX units are clearly printed on the RCXs
themselves, and that a rechargable 9.6v pack is well within those limits
and, indeed, almost the same as powering the units with batteries. The
polarity seems a non-issue to me. I am frankly incensed; having spent
~$2000 on LEGO sets since last November, and considering my continuing
participation in the Mindstorms threaded discussion forum helping out
newbies, I feel I should be a valued customer by now.

Your comments are appreciated (sooner the better; Luwanda's supervisor
should be calling me any time now).
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, preventing damage to the supply in the brick. Your batteries will
have a significantly lower resistance in this regard, and may deliver
instantaneous currents that can damage this circuitry. If this is why the
power input is being dropped, it represents a stupid solution, rather than re-
designing the input circuitry to be self protection...

Best Wishes



Message has 1 Reply:
  RE: External Power Port Problem..?
 
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 (...) (25 years ago, 2-Dec-99, to lugnet.robotics)

Message is in Reply To:
  External Power Port Problem..?
 
Esteemed Colleagues, I have two RCXs, both of which have stopped responding to power applied to the external power port. With batteries, they function correctly; with a 9.6v Lithium Ion battery pack attached to the external port, nothing. This has (...) (26 years ago, 26-Mar-99, to lugnet.robotics)

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