, this soon to be a classic dryer stopped working for the customer and the laundry began to pile up. Based on the age of this unit, there are not many things that can fail so I assured the customer it could be fixed, and got my meter ready to start taking measurements.
Because of the simple nature of the wiring in this unit, the trouble shooting process was simply to figure out where I had voltage, and where I didn't. People can easily become confused while doing voltage checks simply because they are not really sure where to check and what they should be reading. The nice thing about a motor not running on a dryer is the circuit is usually only 120vac, and it doesn't go through to many components.
A good point to always check when the motor won't start is the door switch. As you know, when the door is opened, the dryer shuts off so if the switch were to fail, we would expect the motor not to operate. I started by unplugging the unit and doing a continuity check of the switch. Because this switch (like on most other dryers) completes the neutral path to the motor, it is best to verify it's operation while the unit is unplugged. Using my meter, I was reading continuity when the switch was closed which tells me it is working good.
My next step was to find out where the voltage comes from before it gets to the motor. On this dryer, the timer has both the L1 and L2 circuits running through, so I verified voltage was present to both terminals in reference to ground before proceeding. Then I found the output terminal to the motor was a purple wire connected just below the L1 input. With the timer turned to a cycle, power applied, and the knob pushed to start the motor, I did a voltage check at the purple wire and found 0vac. Voltage going in but not going out is a sure sign of a failed timer assembly.
The replacement timer was in stock, and a couple screws was all it took to replace the old with the new. The dryer took off running and is working great along with the washer next to it from the same era.