You have the U2 ROM chip installed in the U1 socket - this will cause the MPU board to fail the first LED flash. Install it in the U2 socket.
Your pictures are not high resolution enough and I can't tell if U6 is installed 180 degrees out (the label is upside down). The short side of U6 that has the notch should be on the left - look at the RAM chip at U7 underneath it with the notch on the left. If U6 is installed backwards with the notch on the right side then it's now fried.
Any chance solder bridged across two pins?
Quoted from Dewey68:
I did notice that when I first turned the game on the LED was off and I had nothing at TP2.
The voltage for TP2 comes from pin 12 of connector J4 at the MPU board (it comes from the solenoid driver board at J3 pin 11 (red-green wire)). Check the terminal crimps at each end.
MPU board looks pretty clean (no battery corrosion).
I see a bare pin at the bottom of MPU pin header J3 so it looks like the connector J3 plug is sitting up one position too many.