Data East's " Maverick" accepts only a "one player game"

[Mopple]

Hi everybody, 

 

I'm encountering a most peculiar problem with Data East's " Maverick": 

 

I put credits on but when I push the start button it accepts only a one player game, meaning the game starts up fine but when I push the start button again to add players nothing happens! 

 

Strangely enough, sometimes it accepts two players but never three or four, most of the times I can only start at one player game. 

 

It's not the biggest of problems but I still would like to know what could cause this or if anybody has a solution. I'm running rom version 4.02. 

 

As always, thanks in advance!