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Topic: Troubleshooting Suggestions (Read 2995 times) previous topic - next topic


I rebuilt the board from scratch, using all new components and adding a capacitor between the Vcc pin of each shift register and ground.  (It was easier to do it this way than to desolder all of the parts and try to get them off in usable form, and the parts -- resistors, sockets for the shift register chips and connectors -- are all quite inexpensive.)  After a bit more work tracking down and fixing problems, the gizmo was working fine -- or so it appeared.

Once it appeared to be working correctly, I proceeded to what I thought would be the final step, namely attaching the Arduino board and the perfboard to the inside of the enclosure.  Note that the enclosure is plastic, not metal, and I used plastic standoffs in any event, so the problems (which I am about to describe) are not the result of the enclosure itself causing a short.

When I powered it up after screwing down the boards, the LEDs constituting the first die (what the code calls die(0)) continue to work perfectly.  The second set of LEDs, constituting the second die (die(1)), however, are behaving very erratically.  Sometimes they don't come on at all, sometimes they come on but in weird patterns that do not match the patterns of a real die (and do not match the binary numbers which the figurePips function uses to represent those locations), and sometimes one or all of those LEDs come on when they shouldn't (e.g., when the system is first started or when S2 is in "Big Julie" mode (where nothing is supposed to light up because ya gotta remember where da spots formerly wuz)).


THIS IS A CONTINUATION OF THE PREVIOUS POST -- Sorry, I accidently must have hit the "post" button before the message was complete).

I have tried the following:

   1.  Although I did not change the code between the time when it was working OK and the time when the problem showed up, just to be sure I added a few lines which allowed me to use the serial monitor to see what was going on.  The microcontroller appears to be calculating the correct pips to turn on.

   2.  I added a second capacitor to the Vcc pin of the shift register controlling the problematic bunch of LEDs (parallel to the existing capacitor).  The problem persisted.

   3.  On the off chance that somehow the shift register itself got damaged, I swapped it out for a new one.  No dice (no pun intended).

Bottom line is I'm now at a loss as to what else I can do to track this down. :~  Any suggestions?


Rob Rothman

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