I've searched for anyone with exactly this problem and haven't found anything. Apologies if I missed the relevant post.
I've got an F-14 with a Rottendog MPU9211 CPU replacement in it. The only problems I've seen are the jet bumper and the flasher on solenoid 5.
The jet bumper (solenoid 20, transistor Q69) doesn't fire in either the diagnostics or when playing the game. If I have the game in attract mode and ground Q69 the bumper fires. From what I've read that should verify everything from the transistor forward. I've search without success for a schematic for the MPU9211, so I'm not certain what other points to test to trace back further. I've replaced a 6821 that's near Q69 just in case that was bad (U42 was bad when I first installed the board) without getting any change in behavior.
I haven't researched the flasher that isn't working. I only mention it in case there's a known link between these two symptoms.