Electric range's clock/timer went out and oven bake/broil will not operate
I had always wondered why a range outlet needed a Neutral wire. I could understand the need for 240V for the elements but why would we need the neutral to make the 120V loads. Apparently you need the 120V loads for the clock and for the 120V outlet that some stoves have. So it sounds like your 240V loads aren't having a problem but your 120V load (clock) is.
It would be interesting to know what readings you are getting on your receptacle of your plug. Thats definitely the first place to start.

Doing all the possible combinations you should get all these readings

Hot to hot: 240V
Hot to Neutral : 120V
Other Hot to neutral : 120V
Hot to ground: 120V
Other hot to ground: 120V
and Neutral to Ground: 0V

First check by sticking your meter in the front of the plug. Did you get those readings? If so its probably the prongs themselves inside the plug. Sometimes they get loose. So when you stick your range plug in, they just aren't getting good enough contact. A new range plug ($10 will help that). If you don't have a meter, and you don't wanna buy one, I would probably just change the plug (the electrician would have let you know if funny voltages were going on I am sure).
Second, if you did not get those readings check the back of your plug, where the wires connect. Are the screw tight? Did the readings come out properly or are they still wrong? IF they are wrong, Its back to the panel to make sure the neutral and both the hots are not loose in the panel.

Please be as sure as you can the circuit is off! Always make sure there is an indication its on (stove light or element on- than turn off the breaker checking that it turns off). I like the follow up by testing with a meter too, if you have one!