Guide Roller Height Adjustment - LG LH-C6230P Service Manual

DECK MECHANISM ADJUSTMENT

4.Guide Roller Height Adjustment

Purpose: To regulate the height of the tape so that the bottom of the tape runs along the
tape guide line on the Lower Drum.
4-1. Preliminary Adjustment
Test Equipment/ Fixture
Post Height Adjusting Driver
Adjustment Procedure
1) Confirm if the tape runs along the tape guide line of the
Lower Drum.
2) If the tape runs the bottom of the guide line, turn the
Guide Roller Height Adjustment Screw to clockwise
direction.
3) If it runs the top, turn to counterclockwise direction.
4) Adjust the height of the Guide Roller to be guided to the
guide line of the Lower Drum from the starting and end-
ing point of the Drum.
4-2. Precise Adjustment
Test Equipment/Fixture
Oscilloscope
Alignment Tape
Post Height Adjusting
Driver
Adjustment Procedure
1) Play an Alignment Tape after connecting the probe of the
Oscilloscope to the RF Envelope Output Test Point and
Head Switching Output Test Point.
2) Tracking Control(in PB Mode) : Center Position(When
this adjustment is performed after the Drum Assembly
has been replaced, set the Tracking Control so that the
RF Output is Maximum).
3) Height Adjustment Screw : Flatten the RF waveform.
(Fig. C-4-2)
4) Turn(Move) the Tracking Control(in PB Mode) clockwise
and counterclockwise.(Fig. C-4-3)
5) Check that any drop of RF Output is uniform at the start
and end of the waveform.
NOTE
If the adjustment is excessive or insufficient the tape will
jam or fold.
Test Conditions (Mechanism Condition)
Play or Review Mode
Test Equipment Connection Points
CH-1:PB RF Envelope
CH-2:NTSC: SW 30Hz
PAL: SW 25Hz
Head Switching Output
Point
RF Envelope Output
Point
- 4-15 -
Guide Roller Height Adjustment
screws on the Supply and Take-Up
Guide Rollers.
ADJUSTMENT DIAGRAM
Fig. C-4-1
Test Conditions VCR(VCP) State
Play an Alignment Tape
Waveform Diagrams
P2 POST
ADJUSTMENT
P3 POST
ADJUSTMENT
Fig. C-4-2
Tracking Control at center
Fig. C-4-3
Connection Diagram
RF ENVELOPE OUTPUT TEST POINT
HEAD SWITCHING OUTPUT TEST
POINT
Adjustment Point
Guide Roller Height
Adjustment screw
Upper Flange
Guide Roller
Retaining Screw
Adjustment Point
Guide Roller Height
Adjustment Screws
Turn the Roller Guide Height
Adjustment Screw slightly
to flatten the waveform.
Turn(Move) the Tracking
Control to both directions
OSCILLOSCOPE