Toshiba D-VR3SU Service Manual page 97

Alignment and Adjustments
6) Play back the Mono Scope alignment tape (SP mode).
7) Connect an oscilloscope CH-1 to the "Envelope" and CH-2 to the "H'D SW Pulse" for triggering.
8) Turn the guide roller heads with a flat head ( ) driver to obtain a flat video RF envelope as shown in Fig. 6-13.
IDEAL ENVELOPE
S HEIGHT TOO HIGH
S HEIGHT TOO LOW T HEIGHT TOO HIGH T HEIGHT TOO LOW
GUIDE ROLLER S
GUIDE ROLLER T
Fig. 6-13 Guide Roller S, T Height Adjustment
6-9