Omnivision PVQ-1300W, Service Manual

Page: 99 / 175

7.3.4.4.1. How to release from Service Mode:
Press DISPLAY key again on the remote control.
7.3.5. PG SHIFTER ADJUSTMENT
Purpose:
Determine the Video Head Switching Point during Playback.
Symptom of Misadjustment:
May cause Head Switching Noise and/or Vertical Jitter.
Test Point:
TP3001 (TV/VCR Main C.B.A.),
TP6205 (TV/VCR Main C.B.A.)
Adjustment:
PG SHIFTER (EVR)
Specification:
T = 6 H±1 H (0.38 ms±0.06 ms)
Input:
----------
Mode:
SP Playback
Equipment:
Oscilloscope, VHS Alignment Tape (VFMS0003H6)
1. Enter EVR PG Shifter Adjustment mode, refer to " HOW TO ENTER EVR PG
SHIFTER ADJUSTMENT MODE ."
2. Connect the channel-1 scope probe to TP3001 and the channel-2 scope probe to
TP6205. Use TP6205 as a trigger.
3. Adjust value so that the trailing edge of the head switching pulse is placed 6 H±1 H
(0.38 ms±0.06 ms) before the start of the vertical sync pulse.
4. Release EVR PG Shifter Adjustment Mode.
The adjusted value will be written to Memory IC (IC6004).
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