One board has gone bad due to unknown reasons, the second board +5V regulator was blow due to a wiring error (connected 5V to ground).
After 5V regulator replacement, the LED's were not properly operationing on the IR board.
For the remaining two boards, I have replaced the little LM78L05 100 mV regulator with a standard LM7805 (TO-220) package.
I am hoping that this might provide more robustness to operator/wiring errors.
