R Service Manual 19-inch Color Monitor B1997PNST (MD 1998LE)
Service Manual Versions and Revision N o. 1. Ve rs ion R e le as e D ate R e vis ion 1.0 N ov. 21, 2000 O riginal release Copyright Trademarks Copyright 2000 LiteOn Technology Corp. LiteOn is a registered trademark of LiteOn Technology Corp. All Rights Reserved This manual may not, in whole or in part, be copied, photocopied, reproduced, translated, or converted to any electronic or machine readable form without prior written permission of LiteOn Technology Corp.
MD 1998LE (B1997PNST) Table of Contents 1. Precautions.........................................................................................................2 2. Product Specifications .......................................................................................5 3. Operation Theory................................................................................................9 4. Alignments and Adjustments ........................................................................... 14 5.
MD 1998LE (B1997PNST) 1 Precautions Please follow these safety and servicing precautions to prevent damage and to protect against potential hazards such as electrical shock and X-rays. 1-1 Safety Precautions 1-1-1 Warnings 1. For safety purpose, do not attempt to modify the circuit board, and always disconnect the AC power before performing servicing on the monitor. 2. Operation of the monitor outside its cabinet or with the cover removed involves the risk of shock hazard.
MD 1998LE (B1997PNST) 1-1-3 Product Safety Notices Many electrical and mechanical parts in this chassis have special safety-related characteristics which are often not evident from visual inspection, the protection afforded by them may not be obtained by replacing them with components rated for higher voltage, wattage, etc. Before replacing any of these components, consult the Recommended Spare Parts List given at the end of this manual.
MD 1998LE (B1997PNST) d) Plug monitor power cord to the Hi Pot tester terminals. e) Turn on tester and watch the indicator or beeper. f) If the indicator lamp lighten, or beeper beeps, the test fails. 1-4 Ground Continuity Test 1. Test Equipment AC low ohm tester TOS-6100 or equivalent approved equipment. Note : The test equipment must be calibrated in regular period. 2. Test Setup a) Test duration : 3 seconds b) Set current limit at 25 A c) The grounding resistance must be less than 0.1 ohm. 3.
MD 1998LE (B1997PNST) 2 Product Specifications 2-1 Specifications Picture Tube 19-inch (18-inch Visual image area), 95 degrees deflection, dot type black matrix, medium short persistence phosphor, dark bulb,direct etch, Flat square screen with Invar Mask, 0.
MD 1998LE (B1997PNST) 2-2 Signal Cable Pin Connections Table 2-1. Signal Cable Pin Assignment Note: Page 6 Pin Signal Pin Signal 1 Red vi de o 9 +5V ( fr om PC) 2 Gr een vi deo 10 Gr ound 3 Bl ue vi de o 11 Gr ound 4 Gr ound 12 SDA 5* NC 13 H- Sync 6 Red gr ound 14 V- Sync 7 Gr een gr ound 15 SCL 8 Bl ue gr ound This pin is used for selftest detection. Connect this pin to ground at the PC end.
MD 1998LE (B1997PNST) 2-3 Timing Chart This section describes the timings that the computer industry recognizes as standard for computer-generated video signals. Table 2-2. Timing Chart Mode 1 2 3 4 5 6 7 8 9 10 11 12 13 H. Dot s 640 720 640 800 1152 800 1024 1024 1280 1280 1024 1600 1280 V. Dot s 480 400 480 600 864 600 768 768 1024 1024 768 1200 960 31.47 37.93 43.27 46.8 67.5 53.67 60.03 68.67 80 91.146 80 93.75 85.
MD 1998LE (B1997PNST) 2-4 Display Power Management Signal (DPMS) Note: These power-saving states exceed the Environmental Protection Agency (EPA) Energy Star requirements and the Video Electronics Standard Association (VESA) for Display Power Management Signal (DPMS) . Table 2-3.
MD 1998LE (B1997PNST) 3 Operation Theory This is an I2C-bus fully digital controlled multi-sync color monitor, compliant with VESA DDC1/2B and DPMS standards. Besides, it also meets TCO95 and MPRII requirements. It provides user friendly OSM (On-Screen display Menu) controls, and offers the following main features. 3-1 Main Features 1. Simplified chassis design with minimum components. 2. Fully digital controlled via 8-bit microcontroller NT6861AU. 3.
MD 1998LE (B1997PNST) controllable by I2C bus. SDA and SCL signals coming from microprocessor feed to pin 19 and pin 18 to control all functions. 3-3-1 Horizontal Section 1. The oscillator is driven by the currents in R424 and R423. The minimum oscillator frequency is determined by R424 and the maximum frequency is determined by R423. 2. Horizontal sync goes into pin 15 through R314.
MD 1998LE (B1997PNST) 2. In protection mode or out-of-range situation, HUNLock will send 5 V pulse to saturate Q706, then pin 8 of I902 will be low state and open Q509, so G1 will go down to -140V. During the mode change, Mute acts as same as HUNLock’s. 3.
MD 1998LE (B1997PNST) voltage. 2. Regulation The DC O/P voltage is proportional to the auxiliary voltage, so I802 pin 2 senses the feedback voltage from the divider R895, R888, R868, R897 and VR801 to compare with the built-in 2.5 volts reference voltage for error amplifier operation. Finally pin 6 can modulate the different duty cycle by VR801 setting to achieve regulation purpose. 3-4-7 Synchronization 1. Normal Mode The sync pulse from FBT (31 kHz~93.
MD 1998LE (B1997PNST) Horizontal dynamic focus 3-6 Video Amplifier Section 1. RGB signal inputs are terminated by R501, R531 and R561 then pass through the coupling capacitors C502, C532 and C562 to I501 M52743BSP preamplifier. 2. The amplifier RGB signals (0~3 Vpp) are adjusted by I2C bus, pin 19 is for clamp pulse which comes from pin 16 of TDA4856 to set up equal clamp level. 3.
MD 1998LE (B1997PNST) 4 Alignments and Adjustments This section of the service manual explains how to make permanent adjustments to the monitor settings. 4-1 General Adjustments 4-1-1 Adjustment Conditions a) Power Supply Apply AC 115 V or 220 V b) Warm-up Time The monitor must be powered on for 15 minutes before starting any alignment, but requires 30 minutes of warm-up time for convergence adjustment. c) Signal Input 1. Video: RGB Analog, 0.7 Vp-p, positive 2.
MD 1998LE (B1997PNST) 4-2 Alignment Procedures 4-2-1 High Voltage Adjustment CONDITION Display image : Crosshatch pattern PROCEDURE Connect DC meter to TP001 and adjust VR102 to obtain a DC voltage of -152 ± 1V DC . 4-2-2 Screen and White Balance Adjustment CONDITION Switch S701 to factory mode, then press “ ” and ” ” buttons simultaneously when switching the power “On”.
MD 1998LE (B1997PNST) 4-2-3 Focus Adjustment CONDITION Display image : “e” character pattern PROCEDURE 1. Set Brightness and Contrast used for a normal display. 2. Adjust the static focus control on the high voltage resistor block to obtain the best focus over the entire display area. 4-2-4 Static Convergence Adjustments Static convergence involves alignment of the red, blue and green lines in the center area of the display.
MD 1998LE (B1997PNST) Figure 4-2. 4-pole and 6-pole Magnets Movement Blue Blue Red/ Blue Red Green 4-pole m agnets m ovem ent Note : Red/ Blue Red G reen 6-pole m agnets m ovem ent The 4-pole magnets and the 6-pole magnets interact, making dot movement complex. 4-2-5 Degaussing Degaussing is required when poor color impurity appears on the screen. This monitor uses an automatic degaussing circuit that is activated when the power is on.
MD 1998LE (B1997PNST) 5 Troubleshooting 5-1 No Raster No Raster Measure H voltage of B+ at T402 on PWB-MAIN Check I401, Q424, Q416, D409 No 0V Yes Short Circuit at load? T101 pin 2 HV B+ High (50 V or more) Yes Video Check I401, ZD401, Q416, Q424 Yes No Check AC I/P on T805 Yes Check D801 Page 18 HIGH 48 V Normal (40 V, 31.5 kHz) 0V I103, I102 Check voltage of cathode, heater, Grid 1, Grid 2, etc.
MD 1998LE (B1997PNST) 5-2 Function Key Abnormal Function Key Abnormal Check 5V from I810 regulator? No Repair power supply Yes Power ON/OFF again and check X701, oscillator OK? No Replace X701 No Replace I701 No Replace Q701 or Q702 Yes Check I701 uC OK? Yes Check LED LD701 OK? Yes END Troubleshooting Page 19
MD 1998LE (B1997PNST) 5-3 Vertical Scan (Raster is one horizontal line) Vertical Scan Abnormal Check voltage of pin 3 at I301 (about 17.3 V) No Replace I301.
MD 1998LE (B1997PNST) 5-4 R.G.B. Video Amplifier Abnormal RGB Video AMP Abnormal Check the waveform at the I501 pin 29, pin 32, pin 35 No Check B+ (pin17, pin36) No Check B+ pin 10, 6 Yes Check the waveform at pin 2, 6, 11, 19, 27 Yes Check I501 Yes Check the waveform at the I901 pin 3, 5, 1 Yes Check I901 Yes Video signal present at the pin of the CRT R.G.B.
MD 1998LE (B1997PNST) 6 Recommended Parts List Note:1. The components identified by “ exactly the same parts specified. 2. “ mark are critical for X-ray safety. Replace these with There is only OTP IC at the model beginning (FPR stage or before). When it put in mass production and there must be Mask coming out. If you have spart parts need, please use BOM to get the last release part number and related information. No.
MD 1998LE (B1997PNST) No. Location Part Number Description 21 Q802 6426002201 FET N-CHNL SSH 10N 80A 22 I501 6442024210 IC 52743BSP 36P MITSUBISHI 23 R415 6212147254 CF KOHM 4.7 1/4W J T26 MINI 24 ZD401 6414150004 HZ15-2 ZNR 15V/0.5W 25 R803 6203459017 POSISTOR 4.5 DGC3D4R5Q27C 3PIN 26 R802 6201100052 THERMISTOR 10 OHM 8A P=7.5 TKS 27 R822 6221222852 MOF OHM 0.
Page 24 P502B I704 DDC LINE FILTER E2P R O M DDC-SDA DDC-SCL V H LD701 LED INDICATION S702 KEY SCAN PFC CKT DEG CKT I702 I703 E PROM 2 I701 NT6861AU BRIDGE DIODE H V I301 TDA8351 VERT. BOOST T805 POWER TRANS VFLB V- V+ H- D.Y 6.7V 6.1V 5V 82V 17.6V 35.
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