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SERVICE MANUAL
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MODEL VM-1201
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REVISION A0
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DATE MAY. 21. 2001
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DOCUMENT NUMBER
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WARNING ========== For continuous protection against radiation, shock and flame, replace only with same type and rating components specified in the approved sheets. Disclaimer Speco Technologies makes no representation or warranties, either expressed or implied, with respect to the contents hereof and specifically disclaims any warranties, merchantability or fitness for any particular purpose. Furthermore Speco Technologies reserves the right to revise this publication and to mak
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2.4 VERTICAL DEFLECTION BLOCK.........................................……………………..………... 8 2.5 HORIZONTAL DEFLECTION BLOCK.............................……………………............……... 8 3. TROUBLESHOOTING INSTRUCTIONS............................................……………...…….….. 9 3.1 NO DISPLAY, NO POWER.......................…………………………………………………….. 9 3.2 NO DISPLAY, (POWER OK)............………………………………………………………….. 9 3.3 NO DISPLAY, (NO ASTER) ……………………………………………..........…………….. 10 3.4 NO PICTURE O
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Audience This service manual is primarily for system / service engineers, distributors and dealers. It carries the assumption that the reader understands the basic operating concepts. Purpose This manual contains reference data for Speco Technologies monitor. It gives information regarding the operating principles of monitors, as well as technical service and maintenance information. 1. Introduction The VM-1201, high performance monochrome monitor, display over 1,000 TV lines reso
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1.1.2 Signal Input Requirements ‧ Connector For CVBS：BNC terminal Type：composite video input Level：1.0Vp-p Synchronous：0.3 V Luminance：0.7V Polarity：Positive bright Impedance：75 ohms 1.1.3 Power Input Requirements ‧ Operating Voltage Range：90 ~ 264 V at 50 / 60 ±3Hz AC ‧ Input Current at 90 V AC Operating：0.5 Amps rms. maximum ‧ Input Current at 264 V Operating：0.3 Amps rms. maximum ‧ Power consumption Normal operation：30 Watts maximum 1.2 Funct
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• Temperature ：25 ±5℃ • Magnetic field ：No additional magnetic field in near side • AC line Input ：100 ~ 240 V ±10%, 50/60 ±3Hz AC • Warm-up Time ：30 minutes min. after power on and signal applied • Ambient light ：400 to 600 lux. 1.2.1 Display Quality ‧ Display area (monoscope pattern)：full scan ‧ Video Amplifier Performance ‧ Video Bandwidth ：8 MHz ‧ Light output (brightness and contrast at maximum) ‧ At block pattern ：100 FL minimum ‧ At full white pattern ：50 FL minimum ‧ Cont
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‧ Picture geometry：≦ 2.5% ‧ Picture centering：≦ 6mm ‧ Size stability：Picture luminance from 5 FL to max., the size shall be less than 2.5% (with full white pattern) ‧ Swing and jitters：Swing and jitters are not allowed (viewed at 50cm from eyes to screen). ‧ Focus：(viewed at 50cm from eye to screen, contrast adjusted to set luminance at 20 FL with full white pattern, brightness set at raster just disappeared) Inspect full character pattern, all characters should be distinguished. 1.3 Co
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This section describes each functional block of the monitor. 2.1 Main Power Supply Block • AC power input：AC socket • Line input noise / EMI filtering：Line filter T902 ; X-Cap C901, C902. Y-Cap C903, C904, C905. • Over current protection：Fuse • Power on/off control：Power switch • AC to DC conversion and filtering：Diode D901, Capacitor C906 • Start-up circuit：R914, C914. • Main switching power controller, free run oscillation, voltage feed back, switching duty control, cycle by cyc
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• Snubber circuit：Snubber C907, D902, R902. • Primary side self-powering circuit：D903,C914. • Output 13.5 volts for vertical & horizontal drive circuits：D904, C915. • Output 27.5volts for horizontal deflection circuit：D906 ,C916. 2.2 Video input block • Signal input buffering and switch ‧ CVBS Input buffer ：Q201 & R201,R202. • Video filter & output stage. ‧ Video input：Through C202 to W202 (Contrast VR ) and differential amplifier Q202, Q203. ‧ Video amplifier: Cascade amplifier R219,
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black level is stored at pin7 by C404. The slicing level is stored at pin6 by C403 and decided by R403. 2.3.4 Phase detector: The phase detector circuit is connected to pin8. The circuits are activated depending on the voltage of pin18 and the state of the Sync pulse noise detection circuit, C405, C406, R405. 2.3.5 Supply (pin9, 10 and 16): U401 can start operating by application of a very low supply current into pin16. When the starting circuit is taken from pin
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• Flyback generator： ‧ U301 pin6 is the output of the flyback generator that when driven, jumps from low to high condition C305 transfers the jump to pin3 • Vertical size control：VR301, R312, R308. 2.5 Horizontal Deflection Block • Horizontal drive buffering：Driving source-U401 pin11. Driving transistor-Q40, to pull high the driving waveform to drive the Q401(MOS FET). • Horizontal deflection：Horizontal Output transistor-Q401; Load-Yoke inductance and C414 ; D401, High Voltage generati
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3.1.5 If driving pulses at U901 pin6 and drain of Q901 are correct but voltage at U901 pin 7 low than threshold voltage --causing U901 to stop and restart periodically, check and repair following circuits. Power transformer T901 bad; D903 short-circuit/opened. 3.2 No Display, power output normal. 3.2.1 Check and fix FBT B+：If no B+（27.5V）on pin2 of FBT replace D906, C916. 3.2.2 Check driving output voltage：0 or very low check and replace Q402, Q401. 3.2.3 Power off monitor. Check yoke conn
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Appendix A. Spare Parts List Location Parts Number Description F901 28-1100-0006 Fuse, 2A/250V, slow blow D901 06-3100-0005 Diode 3A, 600V, RS407 D902 06-1100-0001 Diode, 1.5A, 800V, BA159 D501, D502 06-1100-0023 Diode, 3A, 800V, FR107 D903, D904, D301 06-1100-0014 Diode, FR1005 D906, D401 06-1100-0058 Diode, 2A, 600V, FR205 Q901 08-3100-0011 Power MOS 2SK2996 Q201, Q202, Q206, Q402, Q501 08-1100-0003 Transistor NPN 2SC1815 Q205 08-1100-0001 Transistor NPN 2SC2688 Q502 08-1100-0002 T
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Appendix B. Schematics and PCB Layout Diagram 1. Schematics Page 1 -- Main Board, Video Board. 2. Schematics Page 2 – Power Supply, Video Amplifier 3. PCB Layout -- Video Board, Circuit Trace 4. PCB Layout -- Main Board, Silk Screen 13
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1 2 3 4 5 6 W204 R515 1 2 330K 3 D C210 D 47U/200V CRT BOARD VR501 2MB R225 680K C902 C903 D901 R222 W902 F901 0.1U/250V 472/400V 3A/600V 8.2K 2W D906 C907 T902 2 .01 1KV HER205 2.5A/250V R914 R902 T901 K 82K 3W 22K 3W 6 7 R223 27.5V 4 C901 HGND 1.5K 1/2W R224 C214 .1U/250V C916 1U/25V 3 150K HEAT 5 8 EC 2200U/50V EE-25 C906 D904 47U/400V 4 R6 R901 FR105 PLUG AC SOCKET C904 4.7 1/4W 560K 472/400V 2 11 13.5V Q205 J501 D902 C C 2SC2688 BA159 R221 CRT SOCKET OPTION W205 12.9V 1K 1 12 C915 L901 R912
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1 2 3 4 5 6 7 8 D D 12.9V R409 C416 270 22U/50V R413 1 5.6K W501 2 3 DY 4 R417 R408 C408 1K 12K 1U R418 L402 Q401 IRF740 12UH 47 R411 R410 C407 30K R411 2.2K 100U/25V 33K L404 C409 Q402 R217 15K B+ 27.5V VR401 2700P R406 2SC1815 C501 H-HOLD 18K R220 10U/250V R416 680 2.7K C411 103 C C 1 C? H.V Q206 U401 TDA2579 R217 C208 2SC1815 15K 4.7U R218 2 R401 6.8K W504 R506 6 C502 820 8.2 2W 223/630V W503 8 3 Q204 7 W502 R311 1 2SC1815 6 7 330K 2 1 C402 C301 5 4 150P 3 2 R315 .15 C402 R403 4 D502 FR107 3
