Subject:
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Voltage problem?
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Thu, 31 Jul 1997 18:44:13 GMT
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Original-From:
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Owen Wessling <owesslin@us.oracle.!IHateSpam!com>
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Viewed:
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1277 times
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Salutations all,
I've got two serial charger boards that are behaving starngely...
At the end of the second assembly stage, after installing the MAX232, I get what appears to
be an improper voltage when the 232's pin 10 is tied to -10 volts. Here's the deal: for the
other tests, the 232 appears fine; using pin 7 of J3 as reference groun, the 232's pin 2 is
+10V, pin 6 is -10V. Checking the voltage across pin 3 of J3 (again, pin 7/J3 is ref) the
voltage is normally -10V, just as is expected. However, when I jumper the 232's pin 6 (-10
ref) to pin 10 (output input) the voltage across pin 3/J3 only rises to about 0V, not the
+10V we expect.
Now, I've checked out the circuit and didn;t find anything that appeared to be wrong; then I
built the second board, to see what it'd do (same results). Now, thinking that identical
cold solder joints/bad capacitors is unlikely, I figured the only possible thing is that
either the expected voltage is wrong (possible, but unlikely), or something's up with
the 232's --- incidentally, the chip I have is not a MAX232, but an AMD232LJN (Jameco
claims its identical). Anyway, I'm looking into that aspect now, but figured I'd throw
this to the list to see if anyone's run into it before.
My thanks,
Owen
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Owen Wessling |
Developer - Companion Products | "He who dies
Visual Development Tools | with the most toys
415.506.4841 | is, nonetheless, still dead."
owesslin@us.oracle.com |
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