Evan Weston just posted a blog entry that chronicled his experience swapping tubes in a Sony PVM monitor. WARNING: Modding or working on CRT’s is extremely dangerous and should only be done by people with the proper skills who understand the risk!!!
Unfortunately for us retro-gamers, CRT’s are no longer made and it’s getting increasingly harder to find ones in good condition. Luckily, many of these monitors use the same tube, regardless of monitor features. That means people with highly-sought after monitors in great condition have a few options available to them, if their tube needs replacing.
Myself, as well as a few other writers / affiliates of RetroRGB.com plan on creating extensive guides and videos on CRT maintenance in the near future that cover everything you’d need. Evan’s blog is a great start though and should point you in the right direction if you’re looking to swap your own tube: https://sneeknet.io/index.php/2019/02/02/pvm-d20l5a-tube-swap