Photo 2 for Watkins 77087 Control IQ2020 Hot Spring, Tiger River, Limelight, 2001-2009.5

Is there any way to tell which board is bad? When I fired up my tub this year, it powered up and worked once. Now it is not powering up. I tried resetting the breaker etc and it still would not power up. A week later I tried it again and it powered up but it quit after a little while and it has remained dead. I confirmed I do have 220 coming in on the heater relay board with appeared to feed the main board. Thanks for your help. Mark