The 24v rail could be shorted. The unit resets itself by shorting the 24v rail momentarily. If an SCC cards develops a short on the 24v rail, it will cause the fixture to constantly reset, never making it to the point of the program where calibration starts. Each flash is a start up cycle, which gets interrupted by the short, causing it to restart. Remove one powered module and reattempt to power up. If failure continues remove next module. Power up again. If it continues you will need to open up the head of the unit and remove the cover plate for the SCC card in the head. Once the cover is removed, find the 4 pin cable with the Red/Black and Blue/Green wire pairs. Remove this header form the SCC card. Carefully power up the fixture long enough to see if the unit will start to calibrate, but do not let the fixture calibrate as the loose covers will get in the way of proper action. When the fixture begins to calibrate, the shorted card has probably been removed unless 1 or more cards have a failure. To verify, reinsert modules that were removed and retest to verify they are still valid. Order the appropriate card and replace.