Toshiba SV-771 has white dot/streak in video output...damaged head?

[doogie812]

12volts points out all the important stuff. If your drum motor was seized it is likely the grounding electrode was damaged.

If it is an external graphite pad remove it, clean it with degreaser, then apply a dab of graphite lube to it.

If the grounding is integral to the motor bearings use a syringe to inject graphite into the bearings race.

Check your DOC (dropout compensater). Depending on how hi end your machine is the DOC will inject black (or the previous video line) for the RC duration of the DOC once triggered.

Getting your head switching back into the VI may make any of the other problems livable or moot.

Good Luck
Doogie