1983 Other Porsche Models 944 WON'T START

HI The 944 was running just fine.
I parked it a t home and now won't start.
Replaced coil, disributor and rotor.
I check power to coil, tester lights up after key turned on.
No spark from the coil or spark plug.
checked fuses, connections etc. all seem appear fine ?
Thanks PATrick H.