Panasonic PV-M1348, Service Manual

Page: 51 / 130

2-28
Eq Pulse
T
1V
5V
One Horizontal Line
Start of V Sync
CH1 : TP3001 CH2 : TP6205
2ms 2 0.1ms
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 (Main C.B.A.)
TP6205 (Main C.B.A.)
Adjustment : PG SHIFTER (EVR)
Specification : T = 6 +/- 1H (0.38 +/- 0.06msec.)
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. Trigger from channel-2.
3. Adjust value so that the leading edge of the head switching
pulse is placed 6H +/- 1H (0.38 +/- 0.06msec.) 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).
Fig. E5
OSD CLOCK FREE RUN FREQUENCY
ADJUSTMENT
Purpose:
To set the OSD clock free run frequency.
Symptom of Misadjustment:
May make it so that on-screen and closed caption display
do not appear.
Test Point : TP3301 (Main C.B.A.)
Adjustment : DOT CLOCK (EVR)
Specification : 2.5 +/- 0.1VDC
INPUT
: Video Input Jack or Antenna Input Terminal
Any video signal, such as a color bar.
Mode : STOP
Equipment : NTSC Video Pattern Generator,
DVM (Digital Volt Meter)
1. Supply any video signal, such as color bar, to the Video
Input Jacket or Antenna Input Terminal.
2. Connect the DVM (Digital Volt Meter) to TP3301 on the
Main C.B.A.
3. Select DOT CLOCK in EVR adjustment mode and adjust
so that the voltage is 2.5 +/- 0.1VDC.