How do I fix a 2-blink error on a Mars/MEI validator?

There are several possible causes. In some cases, the issue may be specific to the model of the machine so review the owner’s manual.

The dip switches may need to be set according to the host machine’s requirements. This is typical if the validator was installed recently.

If the host machine utilizes MDB interface and is the master, clarify that the board is programmed to accept bills.

One of the tubes in coin changer may be empty or very low.

Assuming the coin tube level has adequate inventory, the coin changer can cause this issue. If a tube level sensor in the coin changer is defective, then the actual number of coins is reported incorrectly. To test, install a known working coin changer or have the changer tested at a local service center.

If the host machine’s software requires that the coin levels of the changer are registered, you may need to follow the prefill routine. This information can be located in the owner’s manual of the machine. It will look similar to the example below.

Loading Coins: • Press the “DOWN” button on the keypad until the LCD reads “MANAGE”. • Press “ENTER”. LCD reads “COIN MECH”. • Press “ENTER”. LCD reads “Money $0.00 Load Coins (UP arrow) Unload coins (DOWN arrow)”. • Press the “UP” arrow, and begin loading the coin changer with coins. • Roll the coins in through the coin slot on the front of the Electronic Control Unit or drop them one at a time into the TOP of the coin changer. You will see the money amount on the LCD screen increasing with each coin deposited. A bank roll of nickels, dimes, and quarters are the recommended number of coins to initially load, but load a minimum of $5.05 worth of coins. • When you have completed loading the coins, press the “CANCEL” button 3 times until the LCD reads “Enjoy a Snack and a Beverage”. When $5.05 worth of coins is loaded and the machine is in “sales” mode, the bill accepter’s front blue LED lights will blink.

The best way to rule out the issue is not the validator is by testing it in a known working machine with the dip switches set correctly.

The owner’s manual of the machine is a required resource for all of the above recommendations.