The schematic is in the wiki.
A few quick tests:
Remove the PIC, and power up the board.
- Measure between pin 20 (positive) and 8 (negative) of the PIC socket; you should get 3.3V. If not, look at D1 and U2 (the regulator) and for shorts on the 3.3v rail to ground
- Jumper between pin 20 and pin 4 of the PIC socket. The red LED should turn on. If not, it's likely backwards
- Jumper between pin 20 and pin 11. The green LED should turn on.
- Jumper between pin 11 and 4, and connect the dongle. The green LED should flicker with DMX data. If not, look at U4, jumper JP1, and the input RJ45 jack
/mike