Can you clarify when you do the quick, on/off power up, are the playfield insert lights blinking, or an LED blinking on the MPU?, if it's playfield inserts, it means it's in attract mode? If it is, then you can access the coin door diagnostic switches and set the game to free play, or trigger the coin slot switches to add credits. Once you do this, if you can, you should be able to start a game.
When in attract mode, push the right side diagnostic button, the credit display should read 04 - 01. With batteries not on the board however, you cannot set the game to free play due to the fact you have to power it off to get out of adjustments. So trigger a coin switch and see if it adds credits, push start on the top left front of cab, report back with your findings.