Do you have a SET chip ?
If the light for the bill validator is not coming on its likely that the DBV is not enabled.
Basically the S+ is coin in .... (not dollar, quarter, dime, nickle or penny) Its coin in.
1 coin = 1 credit - the coin simply has to match the sample coin in the coin-comparitor and you got the credit.
So the rhetorical question is.... if you put a $1 bill into the validator how many credits does it give
The S+ by itself does not know denomination.
This is where the SET chip comes in. You pull out your game chip, insert the set chip, run the setup that will tell the validator that its enabled and its a quarter (or whatever) machine.
This way the DBV knows how many credits to give for a dollar. ... some people run quarters or dollars as coin but SET the validator as a penny so they can quickly put on 100 or so credits.
On our main page... bottom right there is RICKS FAQs - it has all the details about how to use a SET chip.