Omnivision PVQ-130W Service Manual page 85

Post Adjustment Driver (VFK0329)
H-Position Adjustment Driver (VFK0330)
7.2.2.3.1. ENVELOPE OUTPUT ADJUSTMENT
The height of the P2 and P3 Posts replacement part is preadjust at the factory.
Purpose:
To achieve a satisfactory picture and secure precise tracking.
Symptom of Misadjustment:
If the envelope is output poorly, much noise will appear in the picture. Then the
tracking will lose precision and the playback picture will be distorted by any slight
variation of the tracking control circuit.
Equipment Required:
Post Adjustment Driver (VFK0329)
1. Place a jumper between TP6003 and +5V(TP6009) on the TV/VCR Main C.B.A. to
defeat Auto Tracking.
2. Eject the tape and insert it again to access the Neutral Tracking position.
3. Play back the alignment tape.
4. Connect the oscilloscope to TP3002 on the Video Signal Process Section of the
TV/VCR Main C.B.A. Use TP6205 as a trigger.
5. Confirm that the RF envelope is flat enough (V1/V-max. is 0.7 or more). If not, with
Post Adjustment Driver, adjust P2 and P3 post height so that the envelope
waveform becomes as flat (V1/V-max. is 0.7 or more) as possible (No envelope
drop). If the envelope drop appears on the left-half of the waveform, adjust P2 post
height. If the envelope drop appears on the right-half of the waveform, adjust P3
post height.
CAUTION:
Overtightening P2 and P3 posts may cause the threads to strip.
Note:
It will be possible to confirm Step 5 according to following steps.
A. Press the Tracking Control Up or Down button on remote control. Make sure
that the envelope waveform remains flat. If not, readjust P2 and/or P3 post
heights.
Fig. M4-1
85