Hello, my 10 yr old mtd yardman mower, won't turn over, I have trickle chg'd the battery (new last year) but when I try to start it it just makes a humming sound. Any help would be appreciated

Check your starter it sounds like it is locked up. Look at wires to the starter follow the one from battery to it and the switch use screwdriver with plastic handle to jump it or try to hook charger to it see if it turns. Start there it is the most common problem.

On a rider the first thing to do is check for 12+ volts at the battery,
-If that is good ceck for volts at the battery side of the solenoid
-Turn key to "Start" position and check for volts at the small wire on the side of the soleniod
-If no volts there a safety switch is probably telling the machine not to start
-if there are volts 12+ then put your volt meter on the starter side of the solenoid
-If there are no volts you have a bad solenoid, If there are 12+ volts the nthe stater is bad.

Good luck and post response
Don