Page 1
Service Guide Specification Model Description MODEL F920BJ BRAND Part No. 3828TSL087F SUFFIX ALEUQ FLATRON F920B Product Name Printing Specification 1. Trim Size (Format) : 215mm x 280 mm 2. Printing Colors • Cover : LG COLORS • Inside : Black 3.
Page 2
D D D D Pagination sheet Pagination sheet English English English English English English English English Cover …. ….. / 2 English Rear PCB 2 Rear Cover Cover Inside Blank Blank Blank...
Page 3
Website:http://biz.LGservice.com E-mail:http://www.LGEservice.com/techsup.html COLOR MONITOR SERVICE MANUAL CHASSIS NO. : CA-130 MODEL: F920B (F920BJ-AL**Q) ) **Same model for Service CAUTION BEFORE SERVICING THE UNIT, READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
SAFETY PRECAUTIONS SAFETY-RELATED COMPONENT WARNING! X-RADIATION There are special components used in this color monitor The only potential source of X-radiation is the picture tube. which are important for safety. These parts are marked However, when the high voltage circuitry is operating on the schematic diagram and the replacement properly there is no possibility of an X-radiation problem.
SERVICING PRECAUTIONS CAUTION: Before servicing receivers covered by this 9. Use with this receiver only the test fixtures specified in service manual and its supplements and addenda, read this service manual. and follow the SAFETY PRECAUTIONS on page 3 of this CAUTION: Do not connect the test fixture ground strap publication.
Page 7
General Soldering Guidelines Replacement 1. Use a grounded-tip, low-wattage soldering iron and 1. Carefully insert the replacement IC in the circuit board. appropriate tip size and shape that will maintain tip 2. Carefully bend each IC lead against the circuit foil pad and solder it.
Page 8
Circuit Board Foil Repair At Other Connections Excessive heat applied to the copper foil of any printed Use the following technique to repair the defective copper circuit board will weaken the adhesive that bonds the foil pattern at connections other than IC Pins. This technique to the circuit board causing the foil to separate from or involves the installation of a jumper wire on the "lift-off"...
TIMING CHART VIDEO SYNC FACTORY PRESET MODE MODE MARK MODE 1 MODE 2 MODE 3 MODE 4 MODE 5 VESA Sync Polarity – Frequency 43.269 53.674 68.677 91.146 93.750 µs Total Period 23.112 18.631 14.561 10.971 10.666 µs Video Active Time 17.778 14.222 10.836...
DISASSEMBLY 1. Carefully place the monitor on a soft cushion 4. Separate the back cover from the latch at the and stand it upright with the cabinet facing bottom of the cabinet using the jig as shown in downward. the figure. 2.
ADJUSTMENT 1. Preparation for Service Adjustment 2. Adjustment by Service Hot key How to enter SVC HOT KEY GENERAL INFORMATION 1. Press Menu and OSD window will appear. 2. While OSD window is displayed, is seen on the All adjustment are thoroughly checked and corrected left bottom of OSD window.
Page 12
4. Distortion 10. Parallelogram Scanning frequency : All Mode (Mode 1~5) Display image : Crosshatch pattern Horizontal : 10 Row Vertical : 8 Row 11. Adjustment of white balance (Adjustment of chromaticity diagram) *(Adjustment of white balance must be made after entering Hot Key Mode and DEGAUSS.) 2.5mm, 2.5mm...
Page 13
11-2. Adjustment of White Balance PROCEDURE After finishing adjustment of cut off (back raster), For trained and experienced service technicians only. approve "Color(15.0) Full white pattern". Use the following procedure to correct minor color Adjust to BDRV Data = 94. purity problems: Adjust RDRV and GDRV to set chromaticity diagram at : x: 0.283 0.003...
Page 14
3. Adjustment Using Service software Program 2. Adjustment for White Balance and Luminance. (Adjustment Program) 1) Set the White Balance Meter. 2) Press the DEGAUSSING on the OSD menu for 1. Adjustment for Factory Mode (Preset Mode). demagnetization of the CDT. 3) Display color 0,0 pattern at Mode 4.
Page 15
- Adjustment and EDID Data Down in GCSC Windows EDID V1.0 User Manual 2. EDID Read & Write 1) Run WinEDID.exe Operating System: MS Windows 98, 2000, XP Port Setup: Windows 98 => Don’t need setup Windows 2000, XP => Need to Port Setup. This program is available to LCD Monitor only.
Page 16
EDID DATA EDIT Item Content Hexadecimal Manufacturer ID 1E6D Product ID 19093 4A95 Year 2004 Version Revision Model name F920BJ Special 0x00 0x01 0x02 0x03 0x04 0x05 0x06 0x07 0x08 0x09 0x0A 0x0B 0x0C 0x0D 0x0E 0x0F 0x00 0x01 0x02 0x03 0x04 0x05...
DESCRIPTION OF BLOCK DIAGRAM 1. Line Filter & Associated Circuit. 5. X-ray Protection. This is used for suppressing noise of power input line This circuit detects the rectified DC voltage comes flowing into the monitor and/or some noise generated from the FBT pin 4. If the high voltage of the FBT in this monitor flowing out through the power input reaches up to about 30kV (abnormal state), H.V control (IC802) detects.
Page 20
12. High Voltage Output & FBT (Flyback Transformer). 18. Static Convergence Control Circuit. The high voltage output circuit is used for generating This circuit corrects the convergence of the screen by pulse wave to the primary coil of the FBT (Flyback supplying the convergence signal to the 4H (STC) coil Transformer (T701)).
TROUBLESHOOTING GUIDE 1. NO POWER NO POWER (POWER INDICATOR OFF) TROUBLE CHECK IN FUSE (F901) FUSE OK?(F901) SMPS Switch (ON, OFF) CHECK TROUBLE IN D901 BRIDGE DIODE? BRIDGE DIODE (D901) CHECK C905(+) VOLTAGE TROUBLE IN 145VDC at 110V input IC901, Q901 310VDC at 220V input IC901, Q901 CHECK...
Page 22
2. NO CHARACTER NO CHARACTER TROUBLE IN IC302 PIN 5, 6, 7? P301, SIGNAL CABLE, PC SIGNAL CHECK TROUBLE IN IC302 PIN 1, 19, 20, 21, 27, 28 IC302, P302 PIN 10 (5V) ? CHECK IC303 PIN 1, 3, 5 TROUBLE IN PIN10 (12V), IC303...
Page 23
3. NO RASTER NO VIDEO (POWER INDICATOR GREEN or AMBER) CHECK AMBER TROUBLE IN POWER INDICATOR P302 SIGNAL CABLE GREEN or AMBER ? GREEN CHECK ROTATE SCREEN CONTROL SCREEN CONTROL KNOB TO CLOCKWISE KNOB OF FBT or COUNTER CLOCKWIES CHECK VOLTAGE AT D924/D926 CATHODE (190V) TROUBLE IN PRIMARY...
6. NO DEGAUSSING NO DEGAUSSING CHECK TROUBLE IN IC401 PIN 6 (5V)? IC401 (MICOM) CHECK TROUBLE IN Q920 COLLECTOR D925 VOLTAGE (0.5V)? CHECK TROUBLE IN P901? P901 TROUBLE IN CHECK RL901 RL901? TROUBLE IN TH901, DEGAUSSING COIL - 24 -...
Page 27
7. H_Deflection Failure 1. Appear the Voltage 15VDC at IC802 Pin 10 replace R838. Q801 Pin 6 waveform is 2. Check IC801 Pins 7~10, 7~6. right? 3. Replace IC801. Q833drain Check Q806, Q807 waveform is right? ZD802, D831. Q832 drain Check Q802, Q803 waveforms are right? Check -12V line.
Page 28
9. S Correction Failure Check S1 ~ S5 signal. Refer to the S-corrction table page? S1~S5 signals are right at Check and replace IC401. each frequency block? Check and replace C833, C854 ~ C859, Q811, Q812, Q836 ~ Q839, Q841~Q844 Cs SIGNAL TABLE HORIZONTAL FREQUENCY(fH)
Page 29
11. Abnormal H_Size The Voltage Repeat the troubleshooting waveforms Q801 Collector Guide of H_deflection failure. are right? 7 T701 pin 1 Replace T701. wareform is right? Check IC802 and around. 12. Side Pin or Trap Failure Check if AC Voltage of IC801 Pin 11 Check and replace IC801,IC401.
Page 30
14. Tilt Failure Check tilt connector connection IC401 Pin 3 output duty varies with Check and replace IC401. different DAC values? IC702 Pin 1 output varies Check and replace IC702. with different DAC values? Check and replace CRT. 15. V Size or Pos. Variation Failure IC801 Pin 12, 13 Check some parts around IC801.
16. High Voltage Failure Q704 gate Check +15 V line. driving pulse exist? ICheck and replace The waveform is right? Q705, Q706, Q707, R710, IC802. Are there some voltages Check and replace (80V, 47V, -160V, etc) Q704, D706, D704 at secondary part of FBT? Done.
Page 32
18. Focus Failure IC801 Pin 32 Check and replace IC801. output are right? Some parts around Replace failed part. Q721, Q723, Q724 and Q725 are right? Some parts around T701 Replace failed part. are right? Check the connection between FBT Pin 13, CRT Socket PCB.
19. Micom Failure IC401 Pin 6 input is over Check IC903. 4.2V? IC401 Pin 8 and 9 Check X401, C406 and C407. inputs are right? Check and replace IC401 Pin 5 input is R443,C730 High Active? All in/output values are Replace IC401.
21. User Control Failure Check connector Ass’y. IC401 Pins 21 and 22 Check and replace function key. inputs are right at each function? Check and replace IC401. Done. 22. Missing Color Proper Video levels are Check signal generator and on P301 Pin 1, 3 and 5. signal cable.
Page 35
23. Visible Retrace Check white balance adjustment. G2 voltage is right? Check G2 control volume and FBT. Blank pedestal is on Check IC302 Pin 19, 20 and 21 of IC302 and related components. Check R775, P302 Assy, Is V_FLB and DC_bias on Q771, D771 and D772 G1 Pin at CRT socket? Done.
24. Unsynchronized Image Compare input sync. of IC401 Pin40 and 41 with output sync. of IC401 33 and 34. Are they all right? Check and replace IC401. Are H_Out and Check and replace IC801. V_Out of IC801 Pin 12,13 and 8 right? Are H_FLYBACK of IC801 Check C832, C843, R801.
26. Misconvergence Check P451 Assy. Proper voltage are Check and replace Q451, Q452, appeared on P451 Q453 Pin 4, 6 Change CRT and readjust convergence. Done. 27. Purity Failure Degaussing Purity is right? Done. Degaussing circuit is right? Refer to 6 NO Degaussing. Replace CRT and verify purity.
REPLACEMENT PARTS LIST CAUTION: BEFORE REPLACING ANY OF THESE COMPONENTS, READ CAREFULLY THE SAFETY PRECAUTIONS IN THIS MANUAL. * NOTE SAFETY Mark AL ALTERNATIVE PARTS DATE: 2004. 3. 30. DATE: 2004. 3. 30. *S *AL LOC. NO. PART NO. DESCRIPTION / SPECIFICATION *S *AL LOC.
Page 41
DATE: 2004. 3. 30. DATE: 2004. 3. 30. *S *AL LOC. NO. PART NO. DESCRIPTION / SPECIFICATION *S *AL LOC. NO. PART NO. DESCRIPTION / SPECIFICATION DIODEs C833 181-482D 184J 18.0*15.0*8.5*7.5 250V C834 0CN1040K949 0.1M 50V Z F TA52 D301 0DS141489AB 1N4148 TP GRANDE DO-34 500MW C835...
Page 42
0.22UH K 2.3*3.4 TP Q726 0TR555109AB 2N5551 TP SAMSUNG TO92 AMP L302 0LA0150K119 AXIAL TAE YANG 0.15UH 10% A Q771 0TR920009AB KSP92 TP SAMSUNG TO92 HIGH V L303 0LA0220K119 0.22UH K 2.3*3.4 TP Q801 0TR558900BA "2SC5589(LG,W/M) BK TOSHIBA T" - 40 -...