There is no such parts layout diagram as far as I have ever seen.
Parts List for the older model. U5 is a LM2931Z50.
I looked at one of mine.
Left of the power transformer near the edge of the case and the large filter capacitor. There is a TO92 voltage regulator. Mine is marked LM2931Z-5. Silk screened with an I for input, O for output and C for common.
The later Surface Mount CM15A is shown in this thread.
http://forums.x10.com/index.php?topic=29278.0Since Dave's web site was moved to a new server. I believe the link to the data maybe broken.
Anyway in the surface mounted version. Near the power transformer is a TO92 type device and the silk screen says "REG" Good bet that is the 5 volt regulator.