Dell does not repair monitors or sell internal monitor components. We do not have monitor repair/disassembly documentation nor do we have internal component troubleshooting data. We simply replace the monitor while under warranty. You could take it to a local TV repair center to see if they can diagnose the issue. Then look for spare parts on 3rd party sites like eBay. You can try these 3rd party repair sites and see if they sell monitor components and have internal troubleshooting documentation:
http://www.lcdrepair.com/
http://www.shopjimmy.com/dell