On Fri, 2 Mar 2012 18:52:18 -0500, "John Smith"
put finger to keyboard and composed:

"Franc Zabkar" wrote in message
.. .
On Sat, 03 Mar 2012 10:00:29 +1100, Franc Zabkar
put finger to keyboard and composed:

When the IC was installed backwards, pins 4 and 6, and pins 3 and 7,
would have been swapped.

If you are wary about the polarity of your ICs, I would use a 9V
battery and a 1.8K series resistor to test the IC. I would connect the
battery's negative terminal to pin #5. This pin is consistent,
irrespective of polarity. I would then connect the battery's positive
terminal, via the resistor, to pins 1 and 9 in turn. I expect that you
should see approximately 1.4V at pin #1 and 3.2V at pin #9.

Thanks Franc, I'll take your advice and do that on Monday with the two
unused parts I have.

I should have said that the above voltages would be with respect to
pin #4. Add about 0.8V when measuring with respect to pin #5.

BTW, I suspect that the 3K resistor on pin #3 would now be open. That
would explain the higher than expected voltage on pin #3.

- Franc Zabkar
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