It is not a power issue. I am using an ATX PSU with 4 units per PCI-e line. Also tried them individually with a dedicated 6A 12V power supply. I am also thinking it must be either the soldering or maybe bad SMDs or something. One unit is showing short-circuit signs with "spark" noise and the ref light flashing really fast. My question is, even if it is bad soldering, are there any changes of getting them to work by redoing the mod? Or are they completely dead now?
One thing I did notice, the damaged units only eat about half watts as the good ones (8-9 watts at the wall while the moded ones are a bit over 15 watts)
Fast red blinking light means the solder is not touching both sides of the resistor. I had one out of the 100 I modded flash red like that. I put the hot air gun on the resistor for 5 sec and it fixed it.