Monitor Repair Manual
At the beginning, you need to depends on monitor repair manual to understand how Monitor circuits work. After you had familiarize how it works, i suggest that you depends lesser on monitor repair manual. By constantly depending on the manual won’t bring much benefits to you as you may think that “with monitor manual then only i can repair a monitor”. It is a wrong concept. You should say, i could repair most monitor even without a schematic diagrams. That’s make you different between an amateur and a pro. However sometimes we do need to refer to schematic for reference like identifying burnt components, look out for missing components part numbers and etc.
Don’t get me wrong, it’s good to have a Monitor schematic diagram besides you but it just that do not fully dependant on it otherwise you may not be able to troubleshoot Monitors that you can’t find the schematic for it.