There is a Laser Cue club thread and you might find info on there.

But the reds are coil +ve supply and will go to the coil at the banded end of the diode. The brown / blue from Q41 will go to the bell switch and the other side of the switch will go to the coil at the non banded diode side. When the coil energises via Q41 the hammer is pulled in to strike the bells and the switch opens to break the coil circuit allowing the hammer to return to rest and this completes the circuit again and so on.

The bell is cool, rings when you drop a target in correct order and when you get extra ball.

It could have been disconnected because of the bell bug.

Get the bonus multiplier up high enough and a special will light on the outlane. Collect the special and the bell will start ringing. The only way to stop the bell is to make the bell ring again by collecting the next ball.

There is an updated from to fix this if it is the problem

Yeah - the bell bug can be pretty annoying even in home use. I ran into it multiple times. I can only imagine how often it would happen on route. I've done the fix to my own eeproms and while it's nice not to get the bug, the alerting of the extra ball is a little lack luster. It sure beats going deaf while playing though!

Hmmm can you point me to where the updated rom is? Shouldn't be too hard to compare original vs. fixed and then fix the fix, as it were. I assume L2 on IPDB is the current, buggy version?

Sounds like the bugged version started the bell on the outlane but then the thread gets killed by the outhole that would normally time/kill the bell, and they forgot to put a line in the next ball thread that would just stop the bell.

What it really should do I'd think is let the special award timer run out before starting the outhole routine.

Looks like it's a manual edit.
https://pinside.com/pinball/forum/topic/laser-cue-rom-hack-to-fix-never-ending-bell

Yeah, I manually edited mine and wrote it. Looks like there is one here too: https://vpuniverse.com/forums/files/file/4192-laser-cue-l-3/?tab=details
Can't speak to its accuracy, but the tags do seem to suggest it also has the bell fix applied.

gotcha, hex edits no problem. Also I can see why it ended up with just the pulse instead of whatever WMS intended it to do. (Likely run the entire activation thread until its end, where it turns it off.... but the thread ID probably lets it get killed by the outhole routine so it never turns off).