zacaj is correct the pulse is too short. If you have a scope you can put it on the outputs and measure the dip when those solenoids fire.

The sound boards can grab a very short pulse.

There's a couple ways to change it. Easiest would be to hack the code. Otherwise you can build a helper board that will grab the signals and lengthen them.

Do not compare Hot Tip and Lucky 7 to later games.... they use the White system OS, not the green that gorgar and system 6 uses. The pulse lengths are likely different.

If I'm reading gorgar's game rom correctly the longest pulse is for 10k signal at 160 milliseconds. The other ones are 32 or 64 milliseconds. (I'm probably not reading it correctly though this is a very, very, cursory glance)

FWIW I added chimes for people with Magic and Ted Nugent (via software) and you have to pulse them longer. I know, different manufacturer, but same concept.

oh, and Cheddar is correct also, they are sending patterns to the later boards, so you'd have to decode that somehow anyway. It's not impossible, but it's a bit of work. An arduino could do and is a bit of overkill, but it's pretty accessible.

Monitor the lines, pass through to the sound/speech board the ones that aren't 'chimes', use the arduino to fire some darlington pairs connected to your chimes.