First, have you put it into test mode and ran the Solnoid tests?

What did you do trying to "fix" the right arm?

Did you verify it wasn't just the Switch that actives that Coil that was the problem? Why are you jumping to conclusion that the coils all blew up, when that is very rarely the case.

Do you have a DMM (Digital Multi Meter) and if so do you know how to use it?

I don't own this game and the FULL manual isn't online anywhere that I can see, but my guess is that when you hit the ball up the left ramp it triggers a switch which fires off the solenoid.

I doubt that anything was wrong with the coil, but you haven't given enough information to determine that.

how long have you had the game?

Did it just stop working out of the blue?

When you were working on the coils did you mess with them with the game on or off?

In your attempts to fix the issue you may have done more damage, possibly blowing fuse that protects both of those coils?

Read over all of my questions and answer everything to the best of your ability it will help me or others help you.

First, it sound like you do have a DMM correct. Lets start with checking your fuses for continuity. If you need help give us the make and model of the DMM. Before we go any further verify your fuses aren't blown. and you need to pop 1 end of the fuse out of circuit to get a 100% accurate test result.

After you do that report back.