Couple of suggestions:

Run an external regulated +12V wallwart, and a single cable from that to the LC. Then regulate the 12V down to the right voltage for each device.

Get a power supply from a later model LC or Quadra 605. That should have a bit more beef to it.

If you have a stronger PS around that is too big for the case, consider cutting a hole in the floor of the LC and hiding it behind the monofoot