S2000 coin in jam issue

[Chanur]

Just bought my first S2000 machine, currently own an S, an S+ and a WMS 4000 Dotmatrix machine. Here goes:
Bought a Wild Double Strike locally from someone just looking to get rid of it. From the coating of dust and grime it had been sitting for quite some time and when we powered it up there  of course it threw a ram error.
Brought it home and walking through this site was able to clear the error. Now have a Coin in Jam error message.
Here's what I've done so far:
Cleaned and reseated the Competitor (13v $.25)
Pulled apart and cleaned the Coin optic {Considering the condition this machine was in it seemed like then next logical step}
Reseated the I/O board.
Checked and reseated the Bill stacker cassette.
Checked the competitor wiring harness and coin optic harness for loose/broken wires.
Here's something I did note: the test button on the Coin optic board did not register a credit when pressed. Based on that I suspect the optic board might be bad? I'd like a few second opinions before I start ordering parts/boards/chips at random.
As this is my first S2000 series machine I have no spares of anything to swap back and forth to see if the problem moves with swapped components. Having said that, what would you gentlemen recommend for a parts inventory? Couple of batteries, clear chips etc?
Little more info, the game is coin in/coin out with a 13v small coin competitor, Date of Manufacture 3/06.
Thanks for any help you can give.
Chris 
 

[RB]

Could be the door I/O or could be that coin in optic. Key & clear chips recommended as well as a spare battery. The green Varta battery needs to be removed if it has one. Also remove the U16 if it's a 1270 MPU. I'm guessing it is being a 2006 manufacture. I have chips as well as other parts. PM me if I can help.

[Chanur]

I can also tell you that while it's in the error mode, the competitor is still kicking coins into the hopper/drop chute instead of rejecting them and if I leave it plugged in, the Diverter solenoid is powered up even with an empty hopper.
I got the machine cheap so I don't mind putting some money into it but don't want tp buy 50 parts to find the one that is the problem.