Maybe this will help someone in the future...
My Dad was complaining that his rather old Maytag electric dryer
smelled like something was burning whenever he used it.
I pulled the front and top and turned it on. A short time after the
heater coils came on, I noticed a burnt smell. I tried a no heat
setting and there was no smell, so it didn't appear to be a belt or
the motor or anything electrical.
I checked the air flow (really strong), I checked the exhaust hose &
vent, etc. and everything was clear.
The one duct I was having trouble checking without taking the entire
dryer apart was the flat duct in the back of the unit where the heat
actually comes into the drum from the heater coil. There is a 3/4"
hole at the top of this duct, but I couldn't shine a light down the
hole and see into it at the same time. Shining a light from inside the
dryer didn't light up lower half of the duct so I couldn't see the
Then I said to myself, "Self, the heater coil throws both heat and
light. Maybe if I start the heater, it will light up the bottom of the
duct enough that I can see if there's anything down there." Sure
enough, as soon as the heater came on, I could see some burnt debris
at the very bottom of the duct.
I turned off the dryer, found a long thin tube in my Dad's shop and
taped it to the end of his vacuum cleaner hose. I stuck the tube into
the hole at the top of the duct, fed it down to the bottom and heard
the debris get sucked up.
When I turned the dryer back on, the smell was gone.
I don't know if it was bugs or paper or what (I didn't feel like
sifting through the vacuum bag) but whatever it was was apparently
burning just a little bit more each time the dryer was turned on.