Check the connectors on the CPU board. I believe the lower or upper right connector is the one that goes to the coin door. Reseat it and see if that changes anything. Check the pins inside the connector housings for corrosion and to make sure none of the pins tabs broke off.

You can also go into switch test and see if the start button is registering.

Parker

I just bought a Trident and it also does not start. I think it is a MPU issues but I wanted to make sure what else I can try before I go out and buy a new board. Trident, when turned on, the speaker makes a loud continuous sound (medium pitched) and will not stop. All the lights turn on and do nothing else. Displays do not show anything I can see it has power.

This is the first STERN I am working on so this is new territory for me. Before I do anything else, wanted to get advise what to do next. Checked fuses and look fine. I do have a multi-meter, what/where should I check the voltages? There is battery corrosion on the MPU but the previous seller stated they had it working. Assuming that all the lights come one and it does play a sound, would indicate that the PS, rectifier and sound board are fine.... is that a safe assumption?

Is there a away to put the board is a diag/test mode?