Yes, there is a replacement available, and a good one too!
A Wyse Winterm terminal module that is configured to work with Beckman Coulter LS6500 liquid scintillation counters is the perfect replacement for old and obsolete CRT monitors that normally come with the LS6500. A fully tested plug and play module configured to work with all Beckman Coulter LS6500, and also guaranteed to work on Beckman LS6000 with serial number 7064XXXX or higher, is available at Service AI. The Wyse module comes with a power supply adapter and a cable to connect with the LS6500.
Installation tips: The Wyse module configured for Beckman Coulter LS6500 is a plug and play device. You will remove your existing CRT monitor and connect the Wyse Winterm module to the same CRT 25 pin port of the LS using the 25/9 pin cable that ships with the Wyse module. You additionally will have to connect any LCD flat screen monitor available with you to the Wyse module using a standard VGA cable.
After the physical connections are done, it will be important to note that the Wyse Winterm should be powered on (using the power adapter that also ships with it) when the LS-6500 is powered on and booting up - just like how it worked when you had the CRT terminal connected to the LS6500.