Problem(s) Encountered:

 Set up the telescope for some engineering work and found that the brakes would not release.  Further investigation found that pneumatic systems--brakes & mirror covers—were nonfunctional through TCS GUI control.  Testing mirror cover actuation using the physical switch on the MDC worked correctly.  It appears that the J2 5-pin socket on the MDC power supply board had loosened just enough to break contact.  Reseating this connector corrected the issue.

Solution:

N/A