That is what it should read using a diode checker.
D46 is good.
5V reg power, Q17 source to R138 to D47 to U3. U3 is an inverting switching regulator. It has current limit capabilities. 5V is fed thru out the board.
At this url http://www.onsemi.com/pub_link/Collateral/MC34063A-D.PDF
you can scroll down to the diagram showing the 5V step down regulation. The first thing to check is the Schottky diode from pin 2 of U3. After that it could be any of a number of things drawing down the 5V, IF IT IS THE 5V THAT IS THE PROBLEM. An O-scope would be best to test, a DMM doesn't have enough impedance to see the 5V getting drawn low, shutting the system down, then resetting. Using a Simpson analog meter one should notice a needle deflection.
The area around the battery contacts is one of the critical areas to check and clean due to battery off gasses.
Schematic of 5V regulator circuit: http://www.robotreviews.com/chat/download/file.php?id=6127&mode=view