3100 Error code Help

[Gerty]

Howdy all.  After performing a ram clear and such my Double Diamond it seemed to work fine, I only played 10-15 games as I had an issue with the arm getting stuck in the down position. The game did pay out a couple of times, two coin wins. I moved the machine to a bench with the hopper removed. I got the lever arm to operate with simple lubrication and such. Now when I boot up I get the 3100 code for an extra coin payout. I opened and closed the door several times and emptied the hopper and looked for jammed coins. I checked the connections that seem to involve the hopper. Still no luck. I must add the machine works fine without the hopper installed. This would point to an issue on the coin out optics no? I'm not sure how to check that out yet. I assume there is a way to energize the hopper motor through the test mode correct? Any ideas? Thanks in advance.

[Gerty]

I took the hopper out cleaned it and made sure everything looked ok. That seemed to do it as now I'm up and running.  Now on to the dead bill validator...