scag sw48 pto wont engage

[mad1208]

scag sw48 blade pto wont engage. switch was bad and replaced it . pto then worked till shut off for a minute tried again and nothing. checked voltage showed 39 volts. unplugged regulater and checked voltage 39 volts ac. replaced regulater and pto switch still 39 volts dc at clutch and clutch shows a resistance of 1 ohm. im lost what should the voltage be and resistance be for coil never had anything like this happen before they either charged or not or charged constant this mower is pull start no battery. noboby i talked to ever had something like this happen. help, help,help. i had hair