If I understand correctly, your T104 240Volt Intermatic timer worked fine before.
Now the clock will not rotate.
The manual switch doesn't operate the load.
You checked for electricity.
But did you check for 240 Volts across terminals 1 and 3?
It sounds like the circuit breaker is tripped off on one leg so circuit has 120V and tests positive for power, but not 240V.
Reset breaker all the way over and then click breaker back.
Back to the timer.
If you test electricity at terminal 1 to ground and it reads 120V, that means timer is receiving power from one leg of the 240 circuit.
If you test terminal 3 to ground and it reads 120V, that means same as above.
But unless you test for 240V across terminals 1 and 3, the tests above mean nothing.
Let's understand 240V circuit.
You know all single-phase household circuits require two wires to complete the circuit.
Same is true for 120V and 240V circuits >> each needs two wires to complete the circuit.
Inside the main breaker box are 3 busbars.
There are 2 hot busbars and 1 neutral busbar.
120V circuit is complete with 1 hot wire from either hot busbar and 1 neutral from neutral busbar
240V circuit is complete with 1 hot wire from one hot busbar and 1 hot wire from other hot busbar.http://waterheatertimer.org/B220C.htmlhttp://waterheatertimer.org/See-inside-main-breaker-box.html
The 240V circuit breaker snaps down over both hot busbars, and then 2 wires come out of that breaker and go to 240V appliance, or to T104 timer terminals 1 and 3.http://waterheatertimer.org/How-to-wire-T104-Intermatic-timer.html
If circuit breaker is not delivering on both those hot wires, then all along the way you can test for electricity and test will show 120V but not 240V.
So it appears as though circuit has electricity, but circuit will not operate until both hot wires are available to complete the circuit.
That's why you test for 240Volt across terminals 1 and 3
And also test for 240Volt across both wires at circuit breaker.
Going back to timer.
Unless there was lightning strike that fried insides of timer, but somehow left everything else untouched, the manual override should work if circuit has 240V, and Load (lights, motor, fan) is operable.
A simple test is to move circuit breaker wires to another 240Volt breaker and see if timer works again.
If breaker will not reset, you will have to replace 240 circuit breaker, or add a subpanel if your busbars are burned and broken.http://waterheatertimer.org/How-to-install-a-subpanel.html