Quoted from EMsInKC:Adjust the 9 position switch so that it just closes at 9 and you'll find it will almost certainly solve your issue. Rarely are the springs the issue.
This.
And you can examine one of the reels that works to get an idea of how it should be set. Take it out and manually step through the numbers, paying attention to the 9-position switch (and the other switches as well, for that matter).