Sony D910B, Service Manual

Page: 104 / 135

6-12
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. 6-16.
Fig. 6-16 Guide Roller S, T Height Adjustment
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. 6-17 Video Envelope Rising when Operation mode Changes from RPS to Play Mode
ENTRANCE SIDE ENVELOPE
(3) Check Transitional Operation from RPS to Play
Check transition from RPS mode to play mode : Using a pre-recorded SP tape, make sure the entry side of envelope comes to an appropriate
steady state within 3 seconds (as shown in Fig. 6-17).
If the envelope waveform does not reach specified peak-to peak amplitude within 3 seconds, adjust as follows :
1) Make sure there is no gap between the supply roller lower flange and the tape.
If there is a gap, adjust the supply guide roller again.
2) Change operation mode from the RPS to the play mode (again) and make sure the entry side of envelope rises within 3 second.