Sony SLV-D920 E1 Service Manual page 26

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
T HEIGHT TOO HIGH
S HEIGHT TOO LOW T HEIGHT TOO LOW
GUIDE ROLLER S GUIDE ROLLER T
Fig. 6-13 Guide Roller S, T Height Adjustment
(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. 6-14).
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.
ENTRANCE SIDE ENVELOPE
Fig. 6-14 Video Envelope Rising when Operation mode Changes from RPS to Play Mode
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