Machine won't start with LCD monitor

hello,

i have a old machine form '99 with industrial computer (DEK 265 gsx stencil printer) and it has two small cathode monitors. one of them broke so me and college replaced it with LCD monitor. machine wont start after this, it only works with cathode monitors. we don't have cathode monitors that small and it is a problem for us. currently we use 19 inch. any idea what can cause this and how can it be solved?

thanks