Hi
@atsugi ,
As has been mentioned, scrollers only have one input and one output, so I too am confused about the two lines going to/from the first
scroller on the PSUs. Would you mind clarifying the setup? Also, are the scrollers Smart Colors or Smart Color PROs and what make and model are the PSUs?
As far as residual
power in the supplies, keep in mind that they supply's output is 24VDC at 10 amps. Once powered off, even with nothing connected, they will discharge rather quickly, mainly due to the fan drawing
power. Even if a
unit was connected very quickly after powering it off, the
unit would immediately drain the
power. The likelihood of anything sparking or arcing is very small. The most likely way you would get any sparks or arcing would be if the
PSU was powered, you had a
return line hooked up, were plugging the male end of a cable into the female
jack on the
PSU or
scroller, and you missed and hit the female
tab and shorted pins 1 and 4 or the +VDC pin and the case.
This seems like the most likely explanation. It is never good to have two PSUs connected together via 4-pin. Check your cabling to be sure that was not the case.
If it would be easier for you to talk things through on the phone,
call me. We can then post an overview of our discussion here for future reference.