Sorry I missed this point from your last post on the Bally thread. It says the SCR is not working.
Pull the lamp driver board out of the game.

Make sure you have zero ohm continuity from:
- The cathode (left) leg of the Q47 SCR to the cathode of any other SCR (all cathodes are connected together to ground).
- The anode (middle) leg of the Q47 SCR to pin 10 of J2 (remember connector pin numbers start from the bottom and count upwards on the lamp driver board)
- The gate (right) leg of the Q47 SCR to resistor R49 just next to it.

Next, test the SCR with your multi-meter (I know you've already replaced the SCR). Set the meter to diode mode.
On the back of the board, put the black meter lead on the SCRs cathode (left) leg and hold it there.
Put the red meter lead on the SCRs anode (middle) leg. You should get NO reading.
Slide the red meter lead along the anode leg until it touches the left gate leg at the same time. You should get a diode reading about 500mv to 600mv.
Now slide the red meter lead off the gate leg while it's still touching the anode leg. You should still be getting the diode reading about 500mv to 600mv because your multi-meter has switched ON the SCR using this process.

Also try it with another SCR to get a feel for the process. You should get a reading between the cathode and anode legs ONLY after sliding the red meter lead across the anode to the gate leg and then off the gate leg.

Just re-attaching the below image for reference.
LDB_SCR_MCR106.jpg