"95, sl600 Starting Problem?

[porschec5]

The engine cranks, but one click at a time (there is a clincking sound behind the dash that is in sync with the cranking. The battery is fully charged and all (known) fuses have been checked. The car was running fine when turned off.
I suspect some sort of alarm malfunction although the key unlocks all doors and allows engine to crank.

Please help!!