The voltage is related to display size, a 17" monitor might run on 27kv while a 32" might run on 34kv, but at higher voltages more X-rays are emitted so most TV

The voltage is related to display size, a 17" monitor might run on 27kv while a 32" might run on 34kv, but at higher voltages more X-rays are emitted so most TVs have safety mechanisms to limit voltage. As for the safety I'd expect anybody servicing arcades to know what they're doing.