To make things a little easier to walk you through it, it will help to know what reel (SS) and game (SP) chips you have. This will be done for each of the 3 optics. Then you will insert something like a piece of cardboard strip into the optics to see if the number on the front of the display changes from 1 to 0. We will use the self test button (by the power switch) to put the unit in 'input test mode'.

So what we need to do, is run a test on the optics. You can remove the optics board (you will need to get to some of the screws from behind the belly glass) to make sure it's clean, but it would be easier to run a test first. The test button on the optics board does not check all of the optics, it just simulates a coin drop. If one of the optics is bad, it won't register a credit. This is a security feature to prevent coins from being pulled back up etc. The coin passes through it blocking the optics in sequence. Next, the coin optics has three sets of optics. a quarter if you are using quarters and if using tokens, it is the same as the tokens you are using). Make sure that the sample coin is the same as what you are using (i.e. Often when people have a problem with the CC, they tied the rake back to force the coins to go to the optics., The problem with doing that is that coins will drop to the hopper even if the machine is not ready to accept them. If it does match,the rake pulls in and it is diverted to the coin optics. If it does not match, it drops to the tray. First when you insert a coin, it goes thought the coin comparator (CC) and is compared with the sample coin that is installed in the back. Did you untie the rake or is it still tied back? In case you don't know, here is the sequence.

Slot machine flashing light