I have the Black and Decker All-In-One Deluxe Automatic Breadmaker B1600 Series and it's worked well for years. Today I put the ingredients for a loaf in the bread pan and when it started to mix the paddle made a very loud clicking noise like it wasn't able to turn properly. When I took the bread pan out I saw that the bottom gear mechanism seemed to be working fine (quietly moving) and so I checked that the pan and paddle were installed correctly. However, when I restarted the machine it still made the loud clicking sound. Any idea what the problem is and how to fix it? Thanks.

There is a sealed bearing in the bottom of the bread pan. The paddle sits on the sealed bearing shaft. Over time the bearing begins to fail and the paddle does not turn freely or it may even freeze up. If you are sure everything is installed correctly this may be the problem. See if the paddle moves freely by hand and is not really loose. Sealed bearings can not be replaced. Eventually you will need a new bread pan. Sorry Hank

It may be the control system detects a fault and won't allow the motor to run.
It may be the belt drive.
The motor may have blown it's fuse.
First, you need to determine how bad the problem is.
It may be a cheap fix, if you are lucky.
My Mom's old Black and Decker All-In-One Automatic Breadmaker b1561 just quit.
I gave it a basic check out.
I tried removing the bread pan and turning the paddle by hand.
It was difficult to turn and I hesitated to use more force as the paddle seems to be cast aluminum .
It would turn on, set the clock, set bread type OK.
When it started to mix, Click! and shut down.
Step 1, I tried the old Black and Decker All-In-One Automatic Breadmaker b1561 to see if it can run without the bread pan installed.
Without the bread pan, it would turn on, set the clock, set bread type OK.
I can let it start the oven and watch it bake nothing.
I did not let it run through the whole process of mixing and baking nothing with no pan or paddle,
as I thought it might be somewhat damaging and why take the chance.
I only wanted to see the motor ran and the oven heated properly.
The bread pan pan mixer paddle bearing was seized and would barely move and my bread maker had protected itself and shut down.
I had that much luck.
The bread pan bearing was not removable.
I could not get only a bearing or bearing and axle.
The pan and bearing was about $60 plus shipping and duty.
I therefore resolved to try to fix the unfixable.
I got out the fire extinguisher to have in emergency.
I put the pan in a soup pot that would hold it upright.
I put 2 tea level tablespoons of coconut oil in the bread pan and wiped most of it around the axle and bearing.
I considered putting some on the outside bottom of the axle but thought that boiling water would only remove it and make a mess to clean up.
Then I put the pot on the stove with enough water to reach the bottom of the pan plus about 1 inch. Then I brought the water to a boil.
Then I turned off the water and let it cool enough tp pick up the bread pan.
I used lineman's pliers to wiggle the axle up and down and clockwise and counter clockwsse for several minutes to loosen it.
Then I test ran it by puting in the pan and paddle then mixing nothing and baking nothing for a short while .
Then I baked a loaf of bread in it.
The user manual instructs to Never immerse the bread baking pan completely in water.
However that seemed to do no damage.
You might first want to try this heating coconut oil and wiggle the shaft with pliers by heating with a hair dryer.
I suggest you test the maximum temperature available from the hair dryer with a thermometer before attempting this .
Make very sure you keep it below the ignition temperature of coconut oil.
It might be wise to have a fire extinuisher on hand to try that.
Best of Luck!