We have more info on Deanna's LEs after a few of us worked together to figure it out -- unsuccessfully.
Any additional ideas will be helpful.
We examined 3 of the 4 units. There were solder points that we touched up, with no improvement. There isn't excessive solder, and no bridging (based on close inspection with a visor).
We had 2 working units from other members that we used to compare the 3 non-working units... after looking at part orientation, soldering, and swapping out all socketed parts -- we came up with nothing. The parts work fine in other units, and working parts still do nothing to help the bad units. We reflashed all of the PICs with current firmware. The PCBs are each v5.
The oddest observation is that the behavior is IDENTICAL across the 3 units in question. board led activity is the same, self-test behavior is the same, voltages (that we checked) were the same.
What is the problem? We have no DMX control of the channels. The led marked "data link" does not light when we have working DMX connected. We can verify the DMX though the other 2 working kits.
Channels do work through the self-test mechanism. We can view the board leds for each channel light in progression, and we can watch strings light up in turn. DMX control is the problem.
Again, we'd swapped out chips to verify them... and swapped them back into the working board to prove that the bad kits are not damaging the replacement chips.
In hindsight, there is one thing we did not check... the regulators. We did not verify each was in the right spot and not swapped. The heat sink had been soldered in place, and rather then remove them to do a closer inspection we left them as-is. Since the self-test worked, and DMX control was the problem we didn't know if regulator swaps might have a role.
We think we can rule out soldering, parts, directionality of chips and capacitors.
Because the problem is IDENTICAL between the 3 units, it seems more likely that there was a bad installation step that was repeated with each unit.
Can anyone offer some ideas?
Thanks!!