Quote Originally Posted by Art View Post
You can measure the current with LEDs running constantly for a single row like it sounds like you're doing.
If it's a POV display where you cycle rows, then no more than one row (or column depending on how you look at it)
is going to be powered at one time, so you can assume the total of the switching transistor and LEDs for a
single row is the maximum current that your display will draw.
The PCB has 12 LED's in parallel. Not sure I completely follow your comment but I'm trying to validate how much current I'm saving by decreasing the duty cycle/frequency. I have an oscilliscope if there's a good way to measure the current with it.

Quote Originally Posted by Art View Post
I believe the best insurance against software failure is your watchdog timer.
Depending on complexity, I suppose some insurance against hardware failure is also prudent.
I've never used the watchdog timer but assume it checks the continuous loop that's running inside the PIC. If so, what happens if the ULN2003 fails or my power supply fails (overvoltage or overcurrent)? The LED's aren't expensive to replace but they are a PITA to access. I want to avoid replacing them at any cost.