1- an HDCD unit will have an HDCD indicator lamp on the front panel
2- to see if it's a power boss unit, pop open to he lid and see if there's a small piggy back PC board stuffed with capacitors above the main PC board. If there's a piggy back board, it's a power boss unit
2- to see if it's a power boss unit, pop open to he lid and see if there's a small piggy back PC board stuffed with capacitors above the main PC board. If there's a piggy back board, it's a power boss unit