I don't have the machine. But I have worked on a few different EM's.

Usually start with getting a manual and schematic.

You can also search the site by you machine as see what others have experienced and how they resolved their issue.

Here are a couple of addition EM sites
http://www.pinrepair.com/em/index.htm
http://www.pinwiki.com/wiki/index.php?title=EM_Repair

So when the motor runs continuously, the EM thinks there is still more to reset.

The manual should have a walk through the start up sequence. I would look step at the and confirm that each in step done.
You can also look a the schematic and see what keeps the motor running and compare the to the start up sequence.

One of the more likely causes on a multi-player is one reel contacts is not recognize it is at zero.

If you can narrow down what part of the start up sequence is not completing, Update your thread.

Good luck it looks like a fun machine.

(I would also update the title of the thread to include reset issues or motor won't stop)

Was it working before this? If not it could be something simple. If not, then get a schematic and get under there!

ball advance unit cleaned up and working. Some may call on you to look at the player unit as well.

coin unit suggests suck coin switch