Welcome! As said above, post a message in the tech section. What cab do you have - UK/Euro build or Japanese build? UK/Euro will have Hantarex Polo or Polo 2 monitors, Japanese will have Nanao MS9-29N or Toei TC-L292. I've never worked on a USA build one but i'd assume they use WG monitors, probably K7400, U2000 or U5000. I assume it's a twin cab as you say 'one of the monitors'.