IMPORTANT: Any time you install or remove components, disconnect power to the unit before you begin. "Hot Plugging" components in this manner can cause even further damage to one or more cabinet components.
Using a multi-meter, measure the power going out of the transformer to the timing mechanism.
The blue wire (between pins 2 and 3) should read approximately 8.5V AC
The orange wire (between pins 1 and 4) should read approximately 29V AC.
If the voltage is okay then the problem is with the timing mechanism and it must be sent in for reconditioning. Create a UPS Shipping Label HERE.
If the voltage is bad, check the voltage going into the transformer. It should read approximately 110V AC. If the voltage is correct, the transformer must be replaced.