LG Electronics L1933TR Circuit Board Foil Repair, At IC Connections, At Other Connections

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Circuit Board Foil Repair

Circuit Board Foil Repair

Excessive heat applied to the copper foil of any printed circuit board will weaken the adhesive that bonds the foil to the circuit board causing the foil to separate from or "lift-off" the board. The following guidelines and procedures should be followed whenever this condition is encountered.

At IC Connections

To repair a defective copper pattern at IC connections use the following procedure to install a jumper wire on the copper pattern side of the circuit board. (Use this technique only on IC connections).

1.Carefully remove the damaged copper pattern with a sharp knife. (Remove only as much copper as absolutely necessary).

2.carefully scratch away the solder resist and acrylic coating (if used) from the end of the remaining copper pattern.

3.Bend a small "U" in one end of a small gauge jumper wire and carefully crimp it around the IC pin. Solder the IC connection.

4.Route the jumper wire along the path of the out-away copper pattern and let it overlap the previously scraped end of the good copper pattern. Solder the overlapped area and clip off any excess jumper wire.

At Other Connections

Use the following technique to repair the defective copper pattern at connections other than IC Pins. This technique involves the installation of a jumper wire on the component side of the circuit board.

1.Remove the defective copper pattern with a sharp knife.

Remove at least 1/4 inch of copper, to ensure that a hazardous condition will not exist if the jumper wire opens.

2.Trace along the copper pattern from both sides of the pattern break and locate the nearest component that is directly connected to the affected copper pattern.

3.Connect insulated 20-gauge jumper wire from the lead of the nearest component on one side of the pattern break to the lead of the nearest component on the other side.

Carefully crimp and solder the connections. CAUTION: Be sure the insulated jumper wire is dressed so the it does not touch components or sharp edges.

Copyright 2007 LG Electronics. Inc. All right reserved.

LGE Internal Use Only

Only for training and service purposes

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Contents CHASSIS NO. LM57B READ THE SAFETY PRECAUTIONS IN THIS MANUALSame model for Service BEFORE SERVICING THE UNITCONTENTS SPECIFICATIONS marked on the schematic diagram and the PRECAUTION WARNING FOR THE SAFETY-RELATEDCOMPONENT Leakage Current Hot Check CircuitSERVICING PRECAUTIONS General Servicing PrecautionsElectrostatically Sensitive ES Devices Small-SignalDiscrete Transistor IC Remove/ReplacementReplacement Removal/ReplacementCircuit Board Foil Repair At IC ConnectionsAt Other Connections TIMING CHART VIDEOSYNC Soft pad on the table DISASSEMBLY-SetOnly for training and service purposes Pull up the stand part1.Pull the front cover upward Only for training and service purposesRemove the screws 3.Put the front face downDISASSEMBLY-Stand In case of Latch #1-1Only for training and service purposes In case of Latch #1DISASSEMBLY-Stand Hold the stand bodyMStarACE BLOCK DIAGRAMLIPS Line BufferBLOCK DIAGRAM-POWER POWERINVERTER 1.Video Controller Part DESCRIPTION OF BLOCK DIAGRAM2.Power Part 3.MICOM PartPRIMARY LIPS Board Block Diagram6.Signal collection Operation description LIPSADJUSTMENT SERVICE OSD Figure 1. Cable ConnectionTROUBLESHOOTING GUIDE 1. NO POWERWaveforms 2. NO RASTER OSD IS NOT DISPLAYED - LIPS 3. NO RASTER OSD IS NOT DISPLAYED - MSTAR Waveforms4. TROUBLE IN DPM Waveforms5. POWER 6. Raster LGE Internal Use Only WIRING DIAGRAMOnly for training and service purposes 6631900109AEXPLODED VIEW Only for training and service purposesLGE Internal Use Only EXPLODED VIEW PARTS LIST Ref. NoDescription Only for training and service purposes REPLACEMENT PARTS LISTSAFETY Mark CAUTION: BEFORE REPLACING ANY OF THESE COMPONENTSFILTERs Only for training and service purposesLGE Internal Use Only TRANSISTORCAPACITORS Only for training and service purposesLGE Internal Use Only TRANSISTORs & ICsOnly for training and service purposes LGE Internal Use OnlyTRANSFORMER Only for training and service purposes SCHEMATIC DIAGRAM1. SCALER LGE Internal Use Only2. POWER & WAFER Only for training and service purposesLGE Internal Use Only 3. INVERTER Only for training and service purposesLGE Internal Use Only 4. POWER Only for training and service purposesLGE Internal Use Only Feb P/NO MFL43002807
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