New flame sensor arrived. Installed. No change. Studied wiring diagram and recalled that my original trouble-shooting indicated defective hi-limit thermostat(dryer worked fine with hi-limit therm. bypassed). Further testing shows 117vac arriving at coil during burn cycle and absent when flame shuts off. AC path goes back to operated heater relay through hi-limit thermostat. Observed AC present at output of operated relay during time burner not burning. Which only leaves the hi-limit thermostat in the circuit. Ordered, received, installed hi-limit thermostat. Dryer works fine!!
In the beginning I had steered away from replacing hi-limit thermostat after reading another post with same conditions and test, with no change after replacing hi-limit therm.
Note: supposedly OEM new hi-limit therm. is rated at 260 degrees with 60 degree spread. The defective therm. is 230 degree with 50 degree spread. Which raises the question---Was this original thermostat the wrong one???
Hopefully, my posting will help the next person doing a similar trouble-shooting.