Hi, I have this yaesu ft 2200 without screen lighting, I know it has 4 3mm bulbs, but I would like to know what voltage I should buy. or in any case how to replace them with led. thank you very much for your help

You can buy 12V or place white 3mm led but you must add a series resistance to the system that already has in each of them that limits the current according to the led you buy. Surely it will be from 1k8, 2k2 to 3k3 the calculated value but you must do it according to what you buy.