I work extensively with the Turbo PMAC Brick. On the face of the device, there are 2 groupings of LEDs.
The upper right corner contains 3 green LEDS that should be on if the 5VDC and 12VDC power is correct.
Near the AMP3 connector, below the Ethernet/USB connectors, there are 4 LEDS.
The top LED is Red and always on in my experience.
The next LED down I've never seen illuminated.
The 3rd LED is red, Label as WD (watchdog). Obviously, we don't want to see that one ON.
The last LED is Green, always on in my experience.
I have pored over the Brick Hardware Ref. Manual and can find no clear description of the LEDS, what colors they may show, and specifically, what they represent. It makes it really hard to diagnose unusual symptoms when you don't know what they are.
