4.73 likely to be the date made.
If it's the type with the white plasstic block at the back with the works in they usual reason for stopping is that the fuse link fails. It's a sprung link that is held by low temp solder. When that overheats it melts and breaks the circuit. Many just fail through age breaking down the solder but a bit of overload can do the same. They come apart fairly easily but take your time over the screws on the back especially the one under the seal (see Pelican link). Low temp solder VERY hard to find for this job so have a look here. Saab clock but the back is the same. Thermal fuse about $1.
http://jlw97.fatcow.com/saabstories/pages/clockfix/
Another here that doesn't use the much easier thermal fuse.
http://www.pelicanparts.com/techarticles/mult_vdo_clock_repair/mult_vdo_clock_repair.htm