Where can I find a schematic of this router

You're asking for a schematic for a router. I doubt that the manufacturer will have one for a consumer "throw away" device. Most simple electronics like routers < $100 items now are considered throw away. I supervised one of the largest electronics service shops in the Denver area and even for us, some schematics were tough to get unless you were an authorized service center.
Sorry

try going to Dewaltservicenet.com and typing in your model number in the middle of the site towards the botttom will pull up a schematic on this and you should be able to download an owners manual from there also.

Have you tried switching channels in the router I have seen suggestions to use challen 1 or 11 instead of the often defaulted 6. You may have increased traffic from your neighbors and non-it devices like wireless phones.