CA, if your screen is very dark even at full brightness you can find the voltage screw at an electron cannon (yep, CRT only) - with that one you can make it as bright as sun
(though it won't live for long like that).
But beware, there are two other screws for focus, so adjust with display turned on, so you know what you are doing.
HIGH VOLTAGE
, use proper tools and equipment. Do this at your own risk, don't say I haven't warned you