I had the same issue and the solution was to exchange all electrolytic capacitors in the power supply. The used "Jamicon" capacitors were all way below their expected values. However the most important capacitor to change is located just next to the switchmode transformer. It is covered with heatshrinkable tubing, so at first I didn't recognize it as a capacitor, and thus exhanging all capacitors on the secondary side helped, the issue didn't go away for good - it still sometimes blinked during startup. This capacitor (10uF/50V) looks like it smoothes a DC voltage to the SMP controller. The ripple voltage across it was substantial and desoldered, it showed som 3.3uF instead of the 10uF it was supposed. Changing it to a new 10uF/50V solved the blinking issue for good.
(I'm aware that the question is old, but I answered it so that new folks with the issue might find this answer when "googling" for aswers)

It sounds like a problem in the effects processor but I am not sure but that would be a starting point.