labsw/LOG: theory that the failures to switch are caused by EMI (on buttons)

labsw/LOG

@@ -195,6 +195,21 @@ Rework:
   - turn-on cycle: all LEDs green, no power (not a reset)
   - 5+ normal cycles
 
+Further analysis: the absence of more abnormal states, such as LEDs
+contradicting relays or LEDs just going dark suggests that the problem
+is may not be USB data corruption. At least some of the symptoms would
+be compatible with EMI from switching the relay creating false signals
+on the buttons.
+
+The "all LEDs green" condition would be a false press of MAIN. The
+CH2 green condition would be harder to explain. Maybe the MAIN LED
+was also green and I didn't notice. In this case, it would have been
+a combination of the MAIN and CH1 buttons (MAIN to exit remote mode,
+turn off all the channels, and enable the channel buttons. Then CH1 to
+turn on CH1 again.)
+
+To do: debounce buttons (in software) before accepting a state change.
+
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 (next PCB run)