LG Electronics TL-AT130M service manual Audio Circuit, No sound in EE Mode No sound in PB Mode

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SECTION3 ELECTRICAL

ELECTRICAL TROUBLESHOOTING GUIDE

4. AUDIO CIRCUIT

(1) No sound in EE Mode

(2) No sound in PB MODE

No sound in EE Mode.

YES

No sound.

YES

Is 5V applied to the IC301

Pin 75?

NO

Check the line of the 5V Line. (Power Circuit)

No sound in PB Mode.

YES

No sound.

YES

Is 5V applied to the	NO
IC301 Pin 75?
IC301 Pin 75?

Check the line of the 5V Line. (Power Circuit)

YES

	Is the Audio signal applied to the		NO
			NO		Check the path of
					Check the path of
	IC301 Pin 76?				LINE/AUDIO.
	IC301 Pin 76?				LINE/AUDIO.

YES

	YES			NO
	YES

	2
	Does the CLK/Data signal(I C)
	Does the CLK/Data signal(I C)
	appear at the IC301 Pin 23, 24?

YES

NO

Check the IC501 Pin 18(CLK),

17(Data) Line.

Does the Audio signal appear

at the IC301 Pin 96?

YES

Check the connection of the Audio

out Jack.

NO

NO

Is the Audio Mute "High" signal applied

to the IC301 Pin 10?

YES

Check the IC501 Pin 2.

(Audio Mute "H".)

Does the Audio signal appear

at the IC301 Pin 1?

YES

Does the Audio signal appear

at the IC301 Pin 96?

Check the connecting State between

the P3D02 Pin 6 and A/C Head.

YES

Is the Audio Mute "H" applied to the IC301 Pin 10?

YES

NO

NO

YES

Does the CLK/Data signal(I2C) appear at the IC301 Pin 23, 24?

YES

NO

Check the IC501 Pin18(CLK),

17(Data) Line.

Replace the IC301		Check the IC501 Pin2.

Replace the IC301

3-9

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Contents KEY Table of Contents Summary Rear FrontVCR Function Indication Indicator PanelIN/OUT Description Terminal Signal LevelsSummary Critical Parts Replacing Time Table Cabinet & Main Frame Exploded Views Cabinet and Main Frame Section Cabinet & Main Frame Section Parts listPacking & Accessory Section Packing Accessory Section Parts listConnection chart of PG adjustment PG AdjustmentNo 24 Power CircuitSMPS No 5.3 aNo 5.2 a to AVCP, Bias Servo Circuit Video is unstable in PB modePB mode When the drum moter stopCapstan motor stops When the capstan motor stopsNo Video in EE Mode No Video in EE ModeC Circuit Pin 16, 40, 55, 58, 87? Clean the Drum Check the System Circuit IC501 PinIs 5V applied to the IC301 Pin 16, 40, 55, 58, 87? Is the EE signal normal?Audio Circuit No sound in EE Mode No sound in PB ModeNo sound in EE Mode No sound in PB ModeNo sound in REC Mode No sound in REC ModeNo cassette tape loading SYSTEM/KEY Circuit Auto StopAuto Stop No F.OSD display No Key displayOSD Circuit No OSD displayElectrical Block & Circuit Diagrams Power Block Diagram Power Clrcuit Diagram Audio Block Diagram C Block Diagram V Circuit Diagram Electrical Block & Circuit Diagrams System Block Diagram Electrical Block & Circuit Diagrams System Clrcuit Diagram Jack Clrcuit Diagram KEY-BOARDCLRCUIT Diagram Electrical Printed Circuit Diagrams Jack P.C.BOARD KEY 1 P.C.BOARD KEY 2 P.C.BOARDMechanism Part Fixing Type Top View Bottom ViewDrum Motor Drum Assembly Fig. A-1-1Fig. A-2-4 Plate Top Fig. A-2-1Arm Assembly F/L Fig. A-2-6 Gear Assembly Rack F/L Fig. A-2-5Holder Assembly CST Fig.A-2-2 Bracket Assembly L/D Motor Fig. A-2-4Head F/E Fig. A-3-2 Arm AssemblyCleaner Base Assembly A/C HeadReel S / Reel T Fig. A-4-4 Brake Assembly T Fig. A-4-1Brake Assembly RS Fig. A-4-2 Arm Assembly Tension Fig. A-4-3Opener Lid Fig. A-5-2 Arm Assembly Pinch Fig. A-5-3Lever T/up Fig. A-5-4 Arm T/up Fig. A-5-5 Lever F/R Fig. A-6-3 Brake Assembly CapstanJust lift the Plate Slider up Gear Sector Fig. A-7-3Lever Tension Fig. A-7-5 Lever Spring Fig. A-7-6Base Assembly P2 Fig. A-8-3/ Base Assembly P3 Fig. A-8-4 Gear Assembly P2 Fig. A-8-1/ Gear Assembly P3 Fig. A-8-2Base Tension Base Loading Base Loading Fig. A-9-1 Arm Assembly Idler Fig. A-9-3Arm Assembly Idler Base Tension Fig. A-9-2Deck Mechanism Adjustment Fig. C-1 Mechanism Alignment Position CheckTorque Gauge 600g.cm ATG Cassette Torque Meter SRK-VHT-303 Checking TorqueTest Equipment/ Fixture Test Conditions Mechanism ConditionGuide Roller Height Adjustment Head Base Audio/Control A/C Head AdjustmentAdjustment Procedure/Diagrams Head Assembly1KHZ 7KHZ Value AdjustmentPrecise Adjustment Azimuth adjustment Adjustment Procedure Adjustment DiagramCheck the Tape Travel after Reassembling Deck Assembly Adjustment after Replacing Drum Assembly Video HeadsCheck before starting repairs Cleaning Required MaintenanceScheduled Maintenance Maintenance ProcedureChassis Bottom Chassis Top GreasingGear Sector Gear Cam Base Loading Gear Drive Gear AY, P2 & P3 Lever, F/R, Base, TensionBase, Tension Mechanism Troubleshooting Guide Auto Stop PLAY/CUE/REV Is the Belt ok? NonoFront Loading Mechanism Cassette does not load Exploded Views Moving Mechanism A11 RUN Date NSP Not Service PartParts Section Screw Description SpecificationAssembly Section Remarks LOCA.NO Description Specification RemarksCapacitor LOCA.NO Description Specification Remark BATTERY,LITHIUMElectrecal section BuzzerLOCA.NO Description Specification Remark NP0 TS Diode CoilHolder DigitronFilter FuseR121 0RD1800F608 R3G6 0RD1800F608 R553 0RD2200F608 R610 0RD2701F608 RESISTOR,DRAWING LOCA.NO Description SpecificationRemote Controller Receiver Remark SwitchZener Diode TransformerVaristor TAL