That is the solid state AC relay (SSR) that turns on the hopper motor via two triacs in series.
Which is why there are three terminals on the input and two on the output.
The three terminals on the input are for the DC control of the triac gates.
One for the top triac in the series triac circuit and the other for the bottom triac.
The third terminal is the DC common for the two control lines.
The triac output is in series with the hopper motor and a 120VAC source.
When both triacs are on the AC current flows through the motor and makes it spin.
If only one triac is on the motor does not spin.
This was a paranoid circuit designed because in the early days it was discovered that the earlier triacs developed were susceptable to "pinch through" due to current leading voltage when an inductive load is switched on and the one triac in would short out and the hopper would spill out all of it's money for free.
A snubber circuit helped the triac survive but the failure rate was still to high.
So two triacs were put in series.
That being said call Larry tomorrow, we have a whole box of SSR's of various types, all tested, give Larry the part number and see if he can match it up. His number is 702-363-9998 and is there from 11 AM to 5PM PST.
Or you can probably find one online at one of the slot parts companies, may be less of a hassle if they take credit cards.