[Vikesrock]

If the DSC 5V light is flashing and the VBatt and 6V lights are solid that likely indicates a short on your 5V line or two identically messed up DSCs. The 5V line is drawn from the VBatt through a DC-DC converter just like the 6V line (separate converters) so if VBatt and 6V are solid, 5V should be too.

Here are some things to try to find the short:
1) Check all wiring to verify that it is correct
2) Check both Digital Sidecars Closely for metal shavings
3) Try powering the system up with nothing connected to the PWM, relay or GPIO on the DSC, add components one at a time until the symptoms return.
4) If you can't find the short through the above it may be some type of dynamic short, check for areas that are uncharacteristically hot after powering up the robot.