Quoted from pete_d:t is possible to replace the CRT with an LCD monitor. I think there's at least one company selling a turnkey package, and you can find discussion online about a full DIY route as well. The trickiest part is finding an LCD screen that has an input compatible with the CGA video from these machines.
My HV combiner lets you use any VGA monitor in Pin2K. Visit my web site (https://www.kahr.us) and look at the third item:
Pinball 2000 H+V Video Sync Combiner kit
-Rob
-visit https://www.kahr.us to get my daughterboard that helps fix WPC pinball resets or my re-engineered Type 1 sound board for classic Williams games