OK, this might be a curly one, or I've just done something stupid. l ran a 36v power cable out to a 36v to 12v DC converter with a 10 amp capacity. On the output side I connected three 100 pixel strings that are rated at 0.3 W per pixel, or 30W for the whole string, so I hope I'm well within the operating limits of the device there. All the pixels lit up when I started a sequence aand then either froze or started to behave erratically. I immediately checked the common ground between the two power supplies running this set of lights (5 such strands in all with 2 strands running off a 12v supply directly) as this sort of behaviourI have seen, in the past, to be associated with confused logic signals caused by no proper V- path common to two or more power supplies. Today, however, I could not get these pixels to sequence no matter what grounding config I used. Set up with two 12v supplies running 12v direct to each string with a common V- between the supplies and controller works fine though. Any ideas and suggestions gratefully accepted.