Burnt smelling clothes from electric dryer?

I just moved into a rental house a few months ago in hopes of buying it, and it came with a few new appliances. The dryer was there but not hooked up yet. The maintenance guy hooked it up and left us the manuals, and I know it was never used before. Right away, loads run at a full length cycle came out smelling burnt. We clean the lint trap after every load, but the only way to avoid the smell is to run it on timed dry in half hour increments. Talked to the landlord and the maintenance guy, and though they are pretty easy to work with, they just keep saying it's because it's new, and needs to be broken in. Well now it's been four months, and it's not new. Same problem. Several people have suggested checking the vent, because it may have already been plugged, or in the time that nothing was hooked up, an animal may have nested there. That sounds likely, but I'm just wondering the best way to go about checking this, and what other possibilities there may be. The vent goes straight down through the floor, and then underneath the dryer and horizontally about 12' before going outside. All the venting past the hole in the floor is covered from below with a drywalled basement ceiling. Can I use something similar to a plumber's snake? One other factor is that the manual states there should be no more than 7' of vent ducting, and it should only be routed up and out, not down. If I can't find anything in the vent, could the routing be a problem? It is a fairly inexpensive Amana electric dryer. Is this problem more common with cheaper machines than expensive ones? Just hoping for some good ideas before I hit up the landlord to send someone out again.