On Thursday 14 June 2007 01:23, Steve Smith wrote:
> Neil:
>
> Maybe consider the three resistor divider outside the pcbs on the panel
> therefore when they are snapped out of the panel the inputs have no input
> except the sensor.. three resistors should then do the whole panel.

Yep, that's what I meant -- the 3R divider will be on the "spare" sections of 
the panel.  Only one 3R divider per panel of 10 circuits and when I remove 
the actual application circuits, the 3R divider will stay on the scrap parts 
of the panel.


> Same as a tester I did for ribbon cable years ago shorts are easy to
> identify and opens as well if you weak pull ups or leds and resistors and
> low for active. Assuming each led is connected via a res to Vcc then with
> the exception of the active (low) all lines should read 1 (opens
> tested)(shorts tested) Duff (short) segments is a little more difficult
> these need a fixture or observation.

You lost me a bit here.  The LEDs are multiplexed -- 3 RA lines go to 
transistors/fets to switch (to ground) the cathodes of the LEDs as 3 columns.  
All RC lines and some RB lines go to the anodes of the LEDs (the rows).


Cheers,
-Neil.
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