LG Electronics TL-AT130M service manual Guide Roller Height Adjustment

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	Test Conditions (Mechanism Condition)	Adjustment Point
• Post Height Adjusting Driver	• Play or Review Mode	• Guide Roller Height Adjustment
		screws on the Supply and Take-Up
		Guide Rollers.

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.

ADJUSTMENT DIAGRAM Guide Roller Height

Adjustment screw

Upper Flange

Guide Roller

Retaining Screw

Fig. C-4-1

4-2. Precise Adjustment
Test Equipment/Fixture	Test Equipment Connection Points	Test Conditions VCR(VCP) State	Adjustment Point
• Oscilloscope	• CH-1:PB RF Envelope	• Play an Alignment Tape	• Guide Roller Height
• Alignment Tape	• CH-2:NTSC: SW 30Hz		Adjustment Screws
• Post Height Adjusting	PAL: SW 25Hz	Waveform Diagrams
Driver	• Head Switching Output
	Point	P2 POST
	• RF Envelope Output
		ADJUSTMENT
	Point

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.		Turn the Roller Guide Height
2) Tracking Control(in PB Mode) : Center Position(When	P3 POST
this adjustment is performed after the Drum Assembly		Adjustment Screw slightly
	ADJUSTMENT
		to flatten the waveform.
has been replaced, set the Tracking Control so that the
		Fig. C-4-2
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)		Tracking Control at center	Turn(Move) the Tracking
5) Check that any drop of RF Output is uniform at the start			Control to both directions
and end of the waveform.		Fig. C-4-3
NOTE
		Connection Diagram
If the adjustment is excessive or insufficient the tape will				OSCILLOSCOPE
jam or fold.
		RF ENVELOPE OUTPUT TEST POINT
	HEAD SWITCHING OUTPUT TEST
	POINT

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