There's a slight burning smell coming from the dryer drum.

DRYER SMELLS LIKE BURNING:

Answer:First, Stop using your dryer until this problem is resolved. This is a fire hazard and could cause a fire.
Your issue is more than likely alint build up problem. The lint that comes off of your clothes as you dry them becomes trapped in the dryer itself and in the venting duct that connects from the back of the dryer to the wall.
The first thing to do is todisconnect powerby unplugging the dryer cord from the wall. Slide the dryer away from the wall slowly.Remove the hose ductthat attaches to the back of the dryer. Look inside the hose duct and if you see heavy lint build up, that is most likely your problem. If you have a shop vac vacuum or similar, use the long wand attachment tovacuum out the lintthat is in the duct. The best way to do this is to completely remove the vent duct from the wall and dryer.Vacuum the inside of the ductto clean it out. Alsovacuum in the vent hole in the wallwhere the duct attaches to the wall and remove any lint that may be blocking air flow. Put everything back together and test your dryer to see if the burning smell has been resolved.


NOTE: There may be heavy build up of lint deep in the wall. You can purchase aDryer Vent Cleaning Kitthat may make your job of cleaning the vent much easier. However, it may be best to call a Dryer Vent Cleaning Company as they have the equipment that is needed to remove all lint in the wall that could cause a fire. We know everyone wants to save money and "do it yourself" but when it comes to safety, money should not be an issue.
If the burning smell is still present, you cantake the dryer apartandtry vacuuming out any lintthat may be built up on the inside of the dryer. Do a search for your dryer model name and number onGoogleto see how your particular dryer model is disassembled. If you are not comfortable taking your dryer apart then it is advised to call an appliance repair company as your issue can cause a fire.
There are other reasons for your dryer to have a burning smell. There could be an electrical issue inside your dryer. This may mean that a certain part or electrical board is going bad or is bad. Another common reason for this issue is something is near the heating element inside the dryer and causing the burning smell. If you have an older clothes dryer, it may be possible that the components are past its life span and it is time to purchase a new dryer. If you want your dryer to be looked at by a professional, it may be time to call an appliance repair company to come out and check your dryer.
There are plenty of videos that can help you to determine what may be wrong with your dryer. There are a few videos below that may assist you with troubleshooting and disassembling your dryer.
The belt
In some dryers, a belt turns the drum. This belt can slip off, which can cause it to start melting. Because it is usually made of rubber, it will then produce a very strong, unpleasant burning odor. If your drum is not turning smoothly or properly, and you notice a bad burning smell, your belt is probably damaged.
THE MOTOR
Dryers have motors, and as they age, they can burn out just like any other motor. This causes a very strong burning smell, and your dryer will either not run at all, or it will run poorly and with a lot of noise.
Read more :http://www.ehow.com/list_7173741_causes-burning-smell-dryer.html
Causes of Burning Smell in Your Dryer eHow

Dryers collect lint.
Some, like the one I fixed last month, had a whole wastebasket full of lint inside it where you could not get it out without tearing the whole dryer apart.
I\'m suspecting either lint or some other foreign object is burning.
For your safety, please take it completely apart, or get someone else who knows what they are doing to do so, before you have a dryer fire.
( P.S. The last dryer I just fixed had a worn out felt on the drum, allowing the blower fan to suck lint past the screen and fill the inside of the dryer with that lint.)
Be blessed.

You will need to open the dryer ans clean the internal duct work.

Lint burns quickly and rarely holds a flame long enough to cause a fire hazard. Metal burning would probably indicate friction on spinning metal, like the motor shaft, or the drum rollers. Plastic/rubber are usually parts that are intended to wear, and can usually be replaced.

Along with the belt, you should also check the idler pulley that takes up the slack in the belt, as well as any drum rollers or nylon glides on the top of the dryer door where the drum rides. Metal, plastic, and lint have distinct smells, and you should be able to determine which one(s) you have by smell.

Lint is a common burner in dryers, and it seems you've looked in some of the obvious places it can accumulate. When you have the cover off, pay special attention to the burner area, and any ducts from the lint screen area. Also, any gaps in insulation where air flows could cause hot spots in the unit. If you can see the flame while its running, make sure its size is not excessive. Flames should not be too low or too high, and should not escape the burner housing.

If you notice soot buildup, your gas/air mixture is off. If you've switched from natural to bottled gas or vice-versa, you may need to swap the burner orifices to match the different pressures of the gas fuel.

Cleanout the exhaust duct ... from the lint screen to the outside vent cover.

I highly recommend opening the dryer by removing the front panel.
Unplug the machine, remove the front cover and be prepared to vacuum out the lint build-up inside the housing of the dryer.
Also clean the exhaust duct of lint buildup too.

Take a flashlight and look inside the drum at the holes on the back end of the drum where the hot air comes in. On mine, there is an air deflector on the back side of the drum and the space between this deflector and the drum was packed with lint. The lint blocked about half the holes. I had to take the drum out, remove this deflector by removing four screws inside the drum then cleaning out the lint. The lint was all brown and scorched.

Make sure the duct to outside is not obstructed. Number one starter of fires with dryers.

you can unplug the unit , and reomve the lower aces panel (3 screws along the front bottom of unit) youll probalby see an excess of lint built up in which case you can vacuum it out, and then check/clean and or replace your dryer vent

You need to check the dryer INTERIOR to ensure there's no lint accumulations on or around the heating element. The exhaust systems on dryers are not perfect and SOME lint often gets by the lint screen and can start the collect inside the dryer. The lint will begin to smolder and give off an odor if it sits on the heating element housing. Make sure the dryer is unplugged before attempting to access the interior. If the model number you provided is correct, the heating element will be located under the drum on the right-hand side. You will need to lift the dryer top and remove the front panel (with the door) to access the inside and vacuum. Let me know if you need further assistance. I hope this information is helpful to you.