Brand new DS (not kit). Had it working on a test bench for a couple of hours.
During the first half hour it would occasionally cycle on and off as I was playing around with it.
It settled down for the last hour so I installed it in my system. Then it just cycled about every 4 seconds. The display goes blank and I hear a click. The it starts over again. Took it out of the system and back on the bench. Same thing. Tried at least 10 power reboots, still bad.