Diagram of the U1100 5v system. Including most of the datasheets.. Some related U1100 repair jobs, Issue, box death, only the 12v 1mA power consumption. 12v to the U1100 is present, but no 5v output. No other lower voltages but the Ohm readings from the P1100 pins are fine. Solution, replace the U1100 for a new one.