As Bob said trigger module is powered by a seperate winding on alt stator & lead(s) to trigger module should only have AC voltage when cranking eng.
Before condeming trigger module/coil try a couple of things 1st.
Locate & disconnect ign kill lead to ign sw at Y/T connector close to ign coil connection,crank eng & check for spark,if you have spark now then problem in lead to ign sw,ign sw itself or safety sw's on tractor(if any).
If still no spark with kill lead disconnected,disconnect AC output leads from alt stator at rectifer/regulator,crank eng & check for spark,if you have spark now then problem in rectifer/regulator,depending on how tractor wired,if output from regulator is wired thru ign sw,if diode(s) in regulator shorted when ign sw turned on this will allow DC battery voltage to backfeed into alt stator & turn same into an electromagnet killing all AC voltage in alt stator.
If still no spark with kill lead/regulator disconnected,then download/save K series service manual at link provided by Bob & follow troubleshooting guide in sect. 8 of manual for solid state ign.