If the problem started when you removed and installed the playfield, then most likely there is a 1-point playfield switch somewhere that is not adjusted properly. When the 1-point score reel is energized, is the 1-point relay also energized at the same time? Check the following switches:

Right rollover button switch - yellow wire and orange wire
Left rollover button switch - yellow wire and orange wire
#1 bumper relay switch - yellow wire and orange wire
#2 bumper relay switch - yellow wire and green/black wire
Standup target switches - yellow wire and green/black wire
Kicker switches - yellow wire and green/black wire

Also, check the switches on the #1 and #2 pop bumpers...