Sony CPD-420GS Training Manual
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Training Manual
CPD-420GS
D98 Chassis
Computer Monitor
Circuit Description and Troubleshooting
Course: MON-03
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Summary of Contents for Sony CPD-420GS

  • Page 1 Training Manual CPD-420GS D98 Chassis Computer Monitor Circuit Description and Troubleshooting Course: MON-03...
  • Page 2: Table Of Contents

    OVP (Over Voltage Protection UVP (Under Voltage Protection) Power Saving Function OCP (Over Current Protection) Self Diagnosis Function Troubleshooting Protection Circuits Timing Specification for CPD-420GS No Power Troubleshooting Troubleshooting Safety Feedback Circuit Troubleshooting Overall Block The AN8037 Power supply Controller...
  • Page 3 RGB Drive Horizontal AFC RGB OUT Horizontal Size Control RGB CUTOFF Pin Keystone, Bow and Geometric Corrections On Screen Display (OSD) Horizontal Centering (Raster only) ASC (Auto Size and Center) Horizontal Linearity Sub Contrast (Cutoff) control Impedance Matching (S CAPS) Brightness and Contract control Horizontal Deflection Shutdown G2 control and Spot Killer...
  • Page 4 Vertical Protection Rotation and Vertical Key Circuits Rotation Vertical Key Convergence Circuits Static Convergence IC704 Dynamic Convergence IC701...
  • Page 5: D98 Chassis Specifications

    Power Consumption D98 Chassis Specifications Maximum 130W Nominal 100W Picture tube 0.25 - 0.27 mm aperture grill pitch 19 inches measured diagonally Deflection frequency Horizontal: 30 to 96 kHz 90 - degree deflection Vertical: 48 to 120 Hz Trinitron AC input voltage / current 100 to 120V, 50/60 Hz, 1.7 A Video image area (18"...
  • Page 6: Power Saving Function

    POWER SAVING FUNCTION NOTE: If no video signal is input to the monitor, the “NO INPUT SIGNAL” message appears. After about 30 seconds, the Power Saving function The monitor has three Power Saving modes. By sensing the absence of automatically puts the monitor into active-off mode and the indicator lights a video signal from the computer, it reduces power consumption as fol- up orange.
  • Page 7: Timing Specification For Cpd-420Gs

    TIMING SPECIFICATION for CPD-420GS M O D E R esolution (H x V ) 720 x 400 1280 x 960 1600 x 1200 D ot C lock (M H z) 28.321 148.500 202.500 H O R IZO N TA L H or.
  • Page 8: Troubleshooting Safety

    Troubleshooting HINT: Troubleshooting Safety Visual inspection can play an essential part in any troubleshooting tech- nique. A Visual inspection of components can lead to the problem area WARNING: and the repair of the circuit at fault. Your eyes may be your best trouble- Before attempting to repair the power supply or any other circuit, safety shooting tools to use.
  • Page 9: Overall Block

    A Board Overall Block The main function of the A Board is to receive incoming video signals and process them into RGB video drives for the CRT. Video signals can be N Board received either from the conventional 15 D-sub connector or via an addi- The N Board is mounted to the D Board via connectors CN1001 and tional 15 D-sub female connector input located on the front of the monitor.
  • Page 11: D Board

    D Board (Convergence) (Power Supply) Both Static and Dynamic Convergence circuits are located on the D Board. The Power Supply, which is located on the D Board, operates very similar The N Board provides these circuits with the necessary geometry param- to previous monitor chassis design such as the D1 chassis.
  • Page 13: Power Supply

    Degauss Circuit Power Supply The Degauss Circuit is used to demagnetize or degauss the CRT. During ‘Active On’ mode, the Micro IC1001/5 (N Board) sets the Degauss signal Overview to digital H (+5V). The Degauss signal via CN1001 pin 25 to CN801 pin The power supply in this unit is a switch mode power supply.
  • Page 14 N B O A R D D B O A R D IC1001/5 VA601 CN1001 D E G A U S S CN601 THP602 CN 801 Q670 R670 RY601 D670 R 6 7 2 R671 F601 4A 250V LF602 FB608 C605 C604 T601...
  • Page 15: Start Up And "Active On" Operation

    Start Up and ‘Active On’ Operation Once start up voltage is applied, IC601/6 (OUT) outputs PWM drive to the gate of Q602 (POWER SWITCH). The PWM frequency will vary between The Power Supply uses a flywheel type switch mode supply. It has both 65kHz to 120kHz depending upon input voltage and power level.
  • Page 17: Regulation

    Regulation IC652/3 is applied to IC603/2 to control the feedback output of IC603/4 while maintaining electrical isolation between chassis ground and AC in- Overall regulation is accomplished by varying the feedback voltage to put ground. The signal at IC603/4 is applied to IC601/9 (FB). As a result, IC601/9 (FB).
  • Page 19: Secondary Voltages

    Secondary Voltages The following voltages are produced by T601 SRT. 5. The output at T601/18 is rectified by D653 and D656 to produce -16V DC and -16V-2 DC used for the deflection circuits. 1. The output at T601/13 is rectified by D650 to produce +183V DC used for deflection and video circuits.
  • Page 21: 'Active Off' And 'Suspend/Standby' Operation

    ‘Active Off’ and ‘Suspend/Standby’ Operation The ‘Active Off’ and ‘Suspend/Standby’ modes are controlled by the ‘RE- MOTE ON/OFF’ signal from the Micro IC1001/7 (N Board). Feedback is The power supply enters the ‘Active Off’ and ‘Suspend/Standby’ mode provided by circuit elements IC603, D631, D632, R662, Q656 and Q658. under the following conditions…...
  • Page 23: Secondary Voltages

    Secondary Voltages 5. The output at T601/18 is rectified by D653 and D656 to produce -12V Under ‘Active Off’ and ‘Suspend/Standby’ modes, the following voltages DC and -12V-2 DC used for the deflection circuits. are produced by T601. 6. The output at T601/10 through R621 is rectified by D648 to produce 1.
  • Page 25: Power Supply Protection Circuits

    OCP (Over Current Protection) Power Supply Protection Circuits OCP is activated if there is excessive current passing through Q602 (POWER SWITCH). R609 is used for current sensing. Current through OVP (Over Voltage Protection) R609 will cause a negative voltage drop in reference to HOT ground. During normal ‘Active On’...
  • Page 27: No Power Troubleshooting

    No Power Troubleshooting (Q602 Troubleshooting) (IC601 Troubleshooting) Q602 can be damaged in various ways such as voltage, current and tem- perature. Check Q602 for shorts. Further checks to F601, R609 and First apply AC to the monitor and check IC601/6 output. If the output at R615.
  • Page 29: The An8037 Power Supply Controller

    The AN8037 Power Supply Controller IC601 The heart or the primary section is the AN8037 Power Supply Controller, IC601. The following table describes the function of each pin. This is TR or Transform er R eset. Sim ilar to a dem agnetization function, this pin detects the falling edge Pin 1 - of the prim ary waveform during relaxation period.
  • Page 31: Troubleshooting Short Circuit Protection

    Secondary Short Circuit Protection 2. The +16V, +12V and +5V DC secondary voltages are monitored Short Circuit Protection for the secondary low voltage supplies are de- through circuit elements D641, Q640 and R641. The +80V DC from tected in different ways. T601 through R641 is applied to Q640 (C).
  • Page 33: Troubleshooting Secondary Circuits

    Troubleshooting Secondary Circuits Troubleshooting Horizontal Centering Failures in these sections are interrelated and one circuit can affect A loss of the Horizontal Centering adjustment can be caused by the fail- another. Consequently, some failures will also affect the primary cir- ures of rectifier diodes, fusible resistors, IC502 and related components.
  • Page 35: +5V Standby Circuit

    +5V Standby Circuit +12V Regulator During ‘Active Off’ and ‘Suspend/Standby’ modes, the +8V DC secondary During ‘Active Off’ and ‘Suspend/Standby” modes, the +16V DC supply is supply applied to IC605/1 (INPUT1) and Q601/C is reduced to +5.5V DC. reduced to +9V DC and is applied to IC605/2 (INPUT2). The ‘REMOTE In order to prevent loss of the +5V DC Standby, it is necessary to supply ON/OFF’...
  • Page 37: Heater Voltage Regulator

    Heater Voltage Regulator Troubleshooting Heater Voltage Heater filament voltage is developed by the +8V DC supply to IC604/1 (I). A loss of Heater Voltage will result in a no picture condition. During ‘Active During ‘Active On’ mode, IC1001/8 (N Board) outputs the “HEATER” con- On’...
  • Page 39: N Board

    DSP Regulator N Board The DSP IC1002 requires +3.3V DC for proper operating. IC1006/3 (O) outputs regulated +3.3V DC to IC1002 pins 9,12, 28 and 52. IC1003 Micro Standby and Reset (N Board) provides IC1002/54 (RESET) with a delayed “RESET” H (+5V) via R1105. The +5V DC Standby supply from IC605 (D Board) is routed to IC1001 The DSP outputs Deflection Drive, Convergence and Geometry Correc- pin 11 and pin 31 providing VCC operating voltage.
  • Page 41: Video And Osd Processing

    The V OUT Sync signal from IC008/21 (V OUT) is routed to the N Board. Video and OSD Processing The H OUT Sync signal from IC008/22 (H OUT) is input to the H DRIVE BUFFER IC006 pin 8 and pin 9. IC006 buffers the H OUT signal which is RGB PREAMP output at pin 4 is routed to the N Board.
  • Page 43: Rgb Drive

    RGB DRIVE RGB OUT The RGB outputs from IC008 are input to the RGB DRIVE IC001 pin 7 (B The RGB outputs from IC001 are applied to RGB OUT IC002 pin 8 (R. IN), pin 9 (G IN) and pin 11 (R IN). The G signal is also low pass filtered IN), pin 9 (G.
  • Page 45: Rgb Cutoff

    RGB CUTOFF The RGB Cutoff levels can only be adjusted via the DAS/CATS software or by the Color Restoration function (explained later). IC1001 on the N board, via the I C data bus controls IC001 D/A outputs at pin 3 (R BKG), pin 4 (G BKG) and pin 5 (B BKG).
  • Page 47: On Screen Display (Osd)

    On Screen Display (OSD) ASC (Auto Size and Center) IC003 (OSD) is the On Screen Display character and graphic generator. The ASC function automatically adjusts for proper size and centering of IC1001 (N Board) via the I C data bus controls IC003 at pin 3 (SDA) and the video image on the screen.
  • Page 49: Sub Contrast (Cutoff) Control

    Sub Contrast (Cutoff) control Brightness and Contract control The Sub Contrast levels can only be set by the DAS/CATS software for The Brightness and Contrast levels can be controlled either by the user or White Balance adjustment. When Sub Contrast is adjusted, the Micro via DAS/CATS software.
  • Page 51: G2 Control And Spot Killer

    G2 control and Spot Killer The G2 source voltage from the D board enters the A board via CN301/1 via R048 and R064. The node between R048 and R064 is connected to the CUTOFF CTRL circuit comprised of IC005 and Q001. The G2 adjust- ment can only be performed using the DAS/CATS Software or the Color Restoration function (explained later).
  • Page 53: Color Restoration

    Color Restoration This digital value of the Red cathode beam current is stored in an indi- vidual register. During the White Balance adjustment via the DAS/CATS software, the average DC level is sensed and stored in the registers. OVERVIEW The Color Restoration function can be performed by the user to restore Color Restoration Function (Red only) the White Balance of the CRT.
  • Page 55: Gpe Graphic Picture Enhancement

    Presentation Mode GPE Graphic Picture Enhancement When the Presentation Mode is selected, IC1001 (N Board) via the I data bus communicates with IC001 (RGB DRIVE). IC001 increases the Overview P-P levels approximately 200mV (5%) of the RGB output signal at pin 20 Through the front panel GPE control, this unit provides the user with the (R OUT), pin 24 (G OUT) and pin 27 (B OUT).
  • Page 57: Plug And Play

    Name Description Plug and Play → Red Video (75 ohm, 0.7V p-p) → GREEN Green Video (75 ohm, 0.7V p-p) VGA (VESA DDC) → BLUE Blue Video (75 ohm, 0.7 V p-p) Reserved VGA = Video Graphics Adapter or Video Graphics Array ...
  • Page 58: What Is Plug And Play

    What is Plug and Play Since the ACCESS.bus conveys information directly to your system, mice and keyboards as well as other compatible components can be plugged Currently there are several levels of Plug and Play compliance. DDC1 and unplugged without having to restart your computer. Especially useful (Display Data Channel 1) capable monitors can communicate with the for monitors, the ACCESS.bus allows you to adjust your screens image display adapter in only one direction through an unused line on the stan-...
  • Page 59: Display Data Channel Circuit

    DDC2B and DDC2AB Display Data Channel Circuit The rear input supports DDC2B and DDC2AB communications. The rear input cable pin 12 (SDA) and pin 15 (SCL) are connected to CN310 pin 2 DDC1 (DDCSCL) and pin 3 (DDCSDA) on the A Board. The data is passed The front input supports DDC1 communications.
  • Page 61: Ddc Data Format (Edid)

    DDC Data Format (EDID) Basic EDID consist of 128 bytes Number Description 8 Bytes Header 10 Bytes Vendor / Product Identification 2 Bytes EDID Version / Revision 5 Bytes Basic Display Parameters / Features 10 Bytes Color Characteristics 3 Bytes Established Timings 16 Bytes Standard Timings...
  • Page 62 NOTES...
  • Page 63: Horizontal Deflection

    Horizontal Deflection Overview The Micro IC1001 and DSP IC1002 (N Board) respond to the Timing and Sync parameters of the video inputs and provide the necessary Horizon- tal Drive and Geometric correction waveforms for the Horizontal Deflec- tion circuit on the D Board. Horizontal Deflection and High Voltage is controlled by IC805 HV / H SIZE REG CTRL.
  • Page 65: Horizontal Afc

    Horizontal AFC The horizontal output pulse of Q505 H OUT is coupled to Q514 H RTRC and buffered. The horizontal pulse H FBP via CN801/ 32 to CN1001/2 (N Board) is input to IC1002/27 (FBP-IN). IC1002 utilizes the H FBP to phase lock the HD OUT signal at pin 25 (HD OUT).
  • Page 67: Horizontal Size Control

    Horizontal Size Control The HD OUT signal from Q502 and Q503 Push-Pull H Drive buffer is also input to IC805/8. IC805 utilizes the HD OUT signal to produce the proper PWM output frequency at pin 20. The DSP IC1002/64 (E/W) output through CN1001/27 to CN801/27 (H.SHAPE) is input to IC805/2.
  • Page 69: Pin Keystone, Bow And Geometric Corrections

    Pin, Keystone, Bow and Geometric Corrections The DSP IC1002 (N Board) pin 64 (E/W) output is also used for Pin, Keystone, Bow and Geometric corrections. IC1002 alters the parabola waveform (H.SHAPE) that is input to IC805/2. IC805/20 outputs the nec- essary PWM drive to Q506 H SIZE REG OUT to control the amount of B+ that is applied to Q505 H OUT.
  • Page 71: Horizontal Centering (Raster Only)

    Horizontal Centering ( Raster only ) Caution: IC502 is powered by a floating supply. Do not attempt to check voltages at IC502 with an O-Scope by attaching a ground lead to T601/17 The Micro IC1001 (N Board) controls the Raster position via the Horizon- (floating ground).
  • Page 73: Horizontal Linearity

    Horizontal Linearity The Micro IC1001/2 (N Board) outputs Horizontal Linearity control via CN1001/28 to CN801/28 (H. LIN BAL) on the D Board. The Horizontal Linearity circuit is comprised of L502 HLC (Horizontal Linearity Coil), T503 LCT (Linearity Coil Transformer) and Q507 HLC CTRL. Horizontal Lin- earity can only be adjusted using the DAS Software.
  • Page 75: Impedance Matching (S Caps)

    1280 X 1024 1600 X 1200 S CAP Switching Q513 Q512 Q511 Q510 Q509 Q508 H Freq. 43.284 kHz 53.545 kHz 68.740 kHz 67.523 kHz 90.894 kHz 74.268 kHz Picture resolutions were generated using Windows 95 “Display Properties” for the CPD-420GS.
  • Page 77: Horizontal Deflection Shutdown

    NOTE: LED illuminates Orange (1.5 seconds) / Off (0.5 seconds). Horizontal Deflection Shutdown Protection The horizontal output pulse of Q505 H OUT is coupled to Q514 (H RTRC) and buffered. The buffered horizontal pulses H FBP via CN801/32 to CN1001/2 (N Board) is input to IC1002/27 (FBP-IN). IC1002 utilizes the H FBP to phase lock the HD OUT signal at pin 25 (HD OUT).
  • Page 79: High Voltage Circuit

    High Voltage Regulation High Voltage Circuit A sample of the HV produced by T901 is output at pin 17. This voltage is Overview divided by (R810, R902, R903, R906, R907, R923 and RV904) and input to IC805/12. This sampled feedback voltage is mixed with the internal The HV (High Voltage) circuit is comprised of circuit elements IC805 (HV triangle OSC and output as PWM drive at pin 18.
  • Page 81: Abl (Auto Brightness Limiting)

    ABL (Auto Brightness Limiting) The ABL circuit is used to control the overall beam current and brightness of the CRT. The T901/11 FBT output is rectified by D904 and filtered by C929. As beam current increases, the voltage output from T901/11 de- creases (current is inversely proportional to the voltage).
  • Page 83: Hv Protection

    ABL Shutdown HV Protection ABL Shutdown is activated when CRT beam current becomes excessive. T901/11 FBT output is rectified by D904 and filtered by C929. As beam HV Shutdown current increases, the voltage output from T901/11 decreases (current is High Voltage protection is performed by monitoring the +300V DC output inversely proportional to the voltage).
  • Page 85: Dynamic Focus (Df) Circuit

    Dynamic Focus (DF) Circuit Overview Two separate Dynamic Focus circuits (Horizontal and Vertical) are incor- porated to provide an increase in the overall sharpness of the picture, especially in the corners of the CRT. Each of these circuits provide their own respective correction waveform.
  • Page 87: Vertical Df

    Vertical DF The Vertical Dynamic Focus circuit is comprised of circuit elements Q706 and Q707. IC1002 DSP (N BOARD) pin 58 (VDF1) outputs the V.DF correction waveform and is applied to Q707, buffered and applied to Q706. Q706 inverts and amplifies the V.DF waveform and via R909 is applied to the Focus voltage at T901/15 FBT.
  • Page 89: Vertical Deflection

    Vertical Geometric Corrections Vertical Deflection Vertical Geometric Corrections can only be performed via the DAS Software. Vertical Size and Centering are the only adjustments Vertical Drive that can be accessed by the user via the OSD menu. The Micro The DSP IC1002 (N Board) pin 1 (VSAWN) outputs the vertical sawtooth IC1001 via the I C bus communicates with the DSP IC1002.
  • Page 91: Vertical Centering

    Vertical Centering Vertical Feedback Pulse Vertical Centering is performed by varying the DC offset of the V SAWN The vertical flyback pulse from IC401/3 through R407 is rectified by D405 waveform in respects to the DCC2 reference voltage. The DC shift is and filtered by C409.
  • Page 93: Vertical Protection

    NOTE: LED illuminates Orange (1.5 seconds) / Off (0.5 seconds) Vertical Protection Vertical Protection The vertical flyback pulse from IC401/3 through R407 is rectified by D405 and filtered by C409. The DC voltage (V.FBP) is routed to the N Board to Micro IC1001/42.
  • Page 95: Rotation And Vertical Key Circuits

    Vertical Key Rotation and Vertical Key Circuits The Vertical Key adjustment can only be performed via the DAS Soft- ware. The DSP IC1002/59 (VDF2) outputs the ‘D.TILT’ triangle wave- Rotation form and is routed to the D Board. The D.TILT waveform via R736 is Rotation adjustments can be made via the user OSD menu and via the applied to the DC reference source, which is input to IC702/1 (+).
  • Page 97: Convergence Circuits

    The DSP IC1002/61 (XSC) outputs the complex convergence waveform Convergence Circuits and is routed to the D Board. The XSC signal is input to IC704/3 (INA-). IC704 current amplifies the XSC signal and the output at pin 1 (IOUTA) is Overview applied to the convergence yoke.
  • Page 99: Dynamic Convergence Ic701

    Dynamic Convergence IC701 The DSP IC1002/8 (YDC) outputs the complex convergence waveform and is routed to the D Board. The YDC signal is input to IC701/2 (+IN B). IC701 current amplifies the YDC signal and the output at pin 1 (OUT B) is applied to the convergence yoke.

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