Touch pad works fine. Any input for microwaving results in vent panel opening, clock counting down, but no microwave power or turntable movement. thanks

There can be a lot of things please check this out :

For turntable foolow these steps :
1..
Check the function. Many microwave models have a timer setting in addition to the cook setting. Check to see that you did not inadvertently choose the timer setting.
2.
Make sure the tray is seated properly. Some trays are seated on a spinning rack that must be aligned in a track. Check to see that the wheels of the tray are aligned. Other models may have a insertion point on the underside of the tray that fits into the spinning motor area. Make sure that the tray is placed squarely over this connector and does not wobble.
3.
Check that the tray is not upside down. If the tray is placed upside down, it may not align properly with the spinning rack or connector. Remove and replace right side up.
4.
Clear the track of debris. Food can stick to the wheels or clog the track in spinning rack models or adhere to the rotators in other models. Remove large pieces of food or other debris and then wipe the interior with a damp sponge.
5.
Turn the turntable function on. Some models may have an on/off switch for the turntable function. Refer to your microwave instructions to see if your model has a switch and how to locate it. Turn it to the "on" position to get the turntable to move again.
IF Microwave doesn't activate
•1
Make sure microwave is plugged in properly.
•2
Check that door closes completely and its latch is aligned.
•3
Check that interlock switch in door works properly (required for activating microwave).
•4
Replace a blown fuse if it's accessible, or contact a service technician.

The problem is your magnetron is not getting power. You may also have a blown fuse inside the microwave. First thing to do is change the fuse, if this does not correct the problem then your charging diode, capacitor, magnetron, or high voltage transformer have failed. It would be cheaper to buy a brand new microwave then to repair it.