Hi All,
Sorry to update an old post, but I have been investigating how to modify my Suzo Happ coin mechs to accept tokens (currently they accept quarters only) and was able to do it today and wanted to share some info.
All the sites I have come across for Happ coin mechs seem to refer to filing down some plastic to get the .984 tokens to be accepted.
When I was looking at my mechs today, I realized the area where I was to file was metal, not plastic, and it was a bracket being held on by a tiny screw that had some locktite (or something to that effect) applied to it. I had to swing back the piece that is hinged on the mech to get to this screw.
By backing out that screw and sliding the bracket back, I was able to my my mechs take .984 tokens and $.25 quarters.
Forgive me if this is not new info....but I had not seen it posted anywhere else in my couple days of searching.
Below are some pics of what I am talking about:
My coin mech:

The screw in question..just by my finger tip:

I unscrewed it and slid the bracket back until it would let my token pass (this is a shot of where it is now):

Coins and .984 tokens now work 100%:

Hope this helps someone in the future if they are reading this post and looking for help!
Jason