If there's a 2nd score reel showing 1 do things work better?

During reset the score motor sends pulses to all of the score reels. Each score reel uses only the number of pulses it needs to get back to zero. There are two switches on each score reel that are used during reset:
2001 100s reel reset (resized).jpg
The one in red in the upper half of the schematic is used to limit the number of pulses that can reach the score reel during reset. Once the score reel shows zero that switch opens to prevent any more pulses from advancing the score reel.

The switch in the lower half of the schematic is used to keep the pulses coming. It closes when the 100s score reel shows a zero. Once the same switch on all four score reels closes the DB/Reset Completed relay fires and the game starts.

Either switch could be misadjusted in your case but I think it's more likely that the switch to the DB relay is stuck closed or is closing too soon.

/Mark

Specials light when the ZB/Sequence Win relay trips. If your top center hole switch were stuck closed, you'd get a special whenever the Score Motor turns via the Motor 2C switch.
2001 center hole (resized).jpg
But if your center hole switch were stuck closed you'd also get a constant 300 points if the Make/Break switch on the ZB relay were working properly. Does the center hole give you 300 points before specials are lit?