Did you check the power supply to verify it's sending out 48V and not less?

Try getting a new SD card and making a brand new image. Stern uses crap SD cards, and when they are corrupted, the machines fail in weird ways.

Instructions on how to make a new SD card image here:
https://sternpinball.com/support/sd-cards/

Also, have you tried swapping node 8 and 9 (and changing the dip switches to reflect the change on the boards) and seeing if that changes anything? They're interchangeable as long as you remember to change the dip switches.

What about swapping node 8 and 9 and seeing if any aspect of the issue changes?

Borygard can fix node boards in many instances. If I had a dead board, I'd definitely try that route before just tossing it.

Do you have another spike2? You can transfer the CPU board, moving the miniSD card and the microsd card at the bottom of the board and figure that out quickly.

Well then, do it the other way. Take the Spike2 board in your bad machine and put it in your good machine and see if the problem moves to your good machine. That way you're not risking the board if the power supply or something else killed it, but can verify if the CPU board is good or not.

Just be sure and swap BOTH the SD cards on the board when you test. The micro-SD is easy to miss.

John and George. Stern's taking literalism to extremes.