The clean internal is not working, is it the power supply ?
In short: check the LEDs
Please make sure all LEDs are on when powered on. All these must be on !
What if one is not on ?
Then we have a problem down-stream.
Firepulse or head bad ?
First, you power-off the base unit, wait 30 seconds (otherwise you will damage the firepulse card !), take off the firepulse card, then switch on the base unit, if you see all lights on now, the power supply is probably good.
If one of the LEDs is off, it might be the backplane.
Second, if the lights are still not all on, power off again, it might be the backplane, mark each connector that you will plug out, so that you plug it back into the right spot. Disconnect those connectors that come from the power supply to the backplane. Switch on the base unit, if you see all lights on now, the power supply is probably good.
If the one of the LEDs is off with just the backplane connected, the backplane is shorting something.
If one of the LEDs is off without anything attached, the power supply is bad.