1. Please choose the Mode Sweep 2-Day (P) - DB preset under \Environmental\Plasma\ column in the Preset tab of Spooky2 software and run it. You will hear the sound of your Ultrasonic if it is good. If you have poor hearing, please ask your family to help.
2. I did a test on a Spooky Central we have here. I used a 12 kHz 5v 100% offset 50% duty cycle signal to the Input, and had the Modulation cable unplugged. No tube was connected, and the Ultrasonic switch was in the UP position.
Please look at the 2 photos attached. Can you please repeat these conditions on your Spooky Central in the method described above. If at all possible, please send photos showing how you performed the test.
Sorry to give you so much work. We need to know what needs replacing.