Despite not having any "power on" indication, there is an indicator in your Monitor 3 output that does relate to tube life. According to discussions I've had with Robert Lutwak, who is the original author of Monitor3, both the DAC gain and Numeric Gain values reported in the Gain Servo section are indicators of tube health. As the cesium depletes in the tube and the beam current decreases, compensation is first made in the firmware by increasing a simple numeric multiplier, "Numeric Gain". When that value reaches 5.00, The hardware DAC Gain is increased by a factor of 2, and the Numeric Gain is reset to 1.00. Over the life of the cesium tube, the DAC Gain value will increase by factors of 2 from 2 to 128. The fact that my unit was experiencing a DAC Gain of only 8 was very gratifying; the fact that yours is showing a value of only 2 is grounds for celebration.