1) ATR or VTR is not resolved (unresolved ATRs or VTRs are unstable!).
2) SMPTE Source is bad (try another tape).
3) Pull Up or Pull Down is being used incorrectly (VSD or SSD).
4) Audio not recorded & played back with Continuous Resync (SDII only).
5) AppleTalk is Active (should be Inactive).
6) Audio Interface crystal has drifted out of spec.

† If the ATR/VTR does not have a built-in Time Base Corrector or is not hooked up to an external TBC, the ATR/VTR will not resolve to any external sync. In one case a caller had a black burst generator that put out sub-carrier sync code to his Sony 5800 VTR, but that model (as well as the more commonly used 5850) does not have a built-in TBC. [Courtesy of Frank Madison @ Sony Tech Support @ 714/220-9100.]