Here are your parts
Model D140

Here is a service manual
http://www.servicematters.com/m...s/16000446(ER001-00).pdf

The timer shows Requires Special Attention often means obsolete but it is worth giving them a call.

Is there anything else that could be wrong besided just the clock.
Usually it is the timer. You could check that all the connections are OK.

How is it repaired.
Replace it
If unavailable there are places that repair mechanical times.
Perhaps someone else will jump in and recommend one.