This document is a service manual for an AKIRA Colour TV, specifically models within the CT-14NI9 group, with the chassis designated as 3S10. The specific model covered is CT-14NI9R, version 1.0. The manual provides comprehensive information for servicing and maintaining the television, including specifications, safety precautions, alignment instructions, and circuit diagrams.
Function Description:
The AKIRA CT-14NI9R is a Colour TV designed for standard television viewing. It incorporates a Hyper-Band Tuner, allowing for reception across a wide range of frequencies. The television supports 100-Channel Memories, enabling users to store and quickly access a large number of channels. It features NTSC Playback, indicating compatibility with the NTSC television broadcast standard, commonly used in North America and parts of South America and Asia. The TV includes both AV Inputs and Outputs, providing connectivity for external devices such as VCRs, DVD players, or gaming consoles. An On-screen Display (OSD) system facilitates user interaction and menu navigation. For user convenience, it includes a Sleep Timer function, which automatically turns off the TV after a set period. The television also offers an Auto Search/Store/Shut-off feature, simplifying channel setup and power management. It comes with a full-function remote control for convenient operation from a distance. Audio is provided by two 3W speakers, offering stereo sound output.
Important Technical Specifications:
- Model Group: CT-14NI9
- Chassis: 3S10
- Model Number: CT-14NI9R
- Tuner: Hyper-Band Tuner
- Channel Memory: 100 channels
- Video Standard: NTSC Playback
- Connectivity: AV Inputs/Outputs
- Display: On-screen Display (OSD)
- Audio: 3W x 2 speakers
- Weight: Approximately 10.5 kg
- Dimensions (W x D x H): 400mm x 355mm x 321mm
- Power Source: 220V (50/60Hz) AC mains
- High Voltage (Normal): 24KV at zero beam current (minimum brightness) under 220V AC power source. The high voltage must not exceed 30KV under any circumstances.
- EEPROM: IC002 (24C08EEPROM) for storing adjustment data.
Usage Features:
The AKIRA CT-14NI9R is designed for user-friendly operation. The full-function remote control allows for easy access to all features. The On-screen Display (OSD) provides a visual interface for navigating menus and adjusting settings. The 100-channel memory and auto search/store function simplify channel management. The sleep timer offers convenience for users who wish to have the TV turn off automatically. AV inputs and outputs allow for versatile connectivity with other entertainment devices.
Maintenance Features:
The service manual emphasizes several critical aspects for maintenance and repair:
X-Ray Radiation Precaution:
- High Voltage Limit: The normal high voltage is 24KV at zero beam current under 220V AC. It must not exceed 30KV.
- High Voltage Check: The high voltage should be checked and recorded as part of the service record during every servicing, using an accurate and reliable high voltage meter.
- Picture Tube Replacement: The picture tube is the primary source of X-Ray Radiation. Any replacement tube must be exactly the same type as specified in the part list to ensure continued X-Ray Radiation protection.
- Safety-Related Parts: Certain parts have special safety-related characteristics for X-Ray Radiation protection. Replacements should only be undertaken after referring to the Product Safety Notice.
Safety Precaution:
- Isolation Transformer: An isolation transformer should be used during dynamic service to prevent shock hazards, as the power supply circuit is directly connected to the AC line.
- Picture Tube Handling: Always discharge the picture tube anode to the CRT conductive coating before handling. Use shatter-proof goggles and keep the tube away from the unprotected body, as a broken tube can violently expel glass fragments.
- Chassis Replacement: Ensure all protective devices (non-metallic control knobs, insulating covers, shields, isolation resistor-capacitor network) are put back in place when replacing a chassis.
- Power Cord Disconnection: Disconnect the power cord when replacing parts or circuit boards.
- High Voltage Resistor Placement: When replacing a high voltage resistor (Metal oxide film resistor), keep it 10mm (1/2in.) away from the circuit board.
- Wiring: Connection wires must be kept away from components with high voltage or high temperature.
- Fuse Replacement: Replace any blown fuse with the FUSE specified in the chassis part list.
Product Safety Notice:
- Many electrical and mechanical parts in the chassis have special safety-related characteristics. These characteristics are identified in the manual and its supplements. Electrical components with such features are shaded on the schematic diagram and part list.
- Substitute replacement parts that do not have the same safety characteristics as specified in the part list may create shock, fire, and X-Ray Radiation or other hazards. Always refer to the part list carefully before replacing any of these components.
Alignment Instruction (3S10):
The manual provides detailed alignment instructions, including:
- Tools Required: TV signal generator, 20MHz/2-channel oscilloscope, Adjust jigs, Sweep Signal Generator (optional), Digital voltmeter, White balance adjust equipment.
- Factory Mode Access: Enter factory mode using MENU, AV, and ANAL keys. Use the OK key to enter Service 2.0 and Design mode. Exit factory mode using the PP key or by pressing STANDBY.
- VCO Adjust: Adjust the TV Signal Generator to output 38.9MHz, stronger than 80dBuV PAL color bar signal. Connect a 220V AC power source. Press AV button after picking out VCO Coarse or VCO Fine items by PROG+/- buttons. VCO is well adjusted automatically if the character OK appears at the bottom of the screen. If OK does not appear, manually fine-tune C2238 (piezo-type ceramic resonator).
- Trap Adjust for RF NTSC: Receive RF NTSC signal. Adjust LC101 until the picture is best.
- AGC Adjust: Receive 60dBuV RF signal. Enter Service V2.0 mode and get Tuner AGC PAL item. Adjust PAL AGC by VOL+/- buttons until the picture's noise just disappears and its distortion is under 100dBuV level.
- Main Power Adjust (B+): Switch on power, measure the voltage with a digital voltage meter between two terminals of C615. Adjust VR601 to obtain 110+/-0.5V on the Digital Voltage meter.
- TV General Adjust (G2): Set TV set to factory mode without signal input. Press MUTE button, a horizontal line appears. Adjust the "SCREEN" knob of FBT until a horizontal line is just seen. Press MUTE button to exit one line mode.
- Focus Adjust: Receive CROSS HATCH PATTERN, set picture to Dynamic statue by pressing PP button. Adjust the "FOCUS" knob of FBT to get a clear picture.
- White Balance Adjust: Receive black & white pattern (PAL SYSTEM). Set picture to Static statue, adjust white balance equipment to get 2cd/m2 at low brightness and 100cd/m2 at high brightness. Enter white balance adjust mode of factory mode. Two probes of white balance equipment close up the low brightness and high brightness area. Adjust Red Gain, Green Gain, Blue Gain, DC Red, DC Green, DC Blue (DC Blue is better to fixed to 64) using remote handset to meet factory requirement.
- Horizontal/Vertical Central Adjust: Receive MONOSCOPE PATTERN. Set H position item, use VOL+/- buttons to set H center of the picture to meet factory requirement. Vertical central can not be adjusted by IIC bus. It can be adjusted using a 1.5K/2W resistor (R312 or R311).
- SUB-Brightness Adjust: Enter Service V2.0 mode. Press PROG+/- buttons to select Bright Max. Set a fixed value by VOL+/- buttons. Adjust Bright Min item and bright, contrast, color become zero automatically. Press VOL+/- buttons to make the second darkness bar of GREY SCALE part loom. Press PIC again to exit this mode.
- Vertical Amplitude Adjust: PAL system: adjust under VAMP 50. NTSC system: adjust under VAMP 60.
- Sub-Tint Adjust: Receive NTSC RF signal. Set main Tint to center (zero). Set TV set to SERVICE V2.0 mode and get Sub Tint item. Adjust SubTint using VOL+/- buttons until tint is best.
- Picture's Standard Data: Adjust brightness/contrast/color to the best mode. Enter white balance adjust mode, then press S.MODE key. MCU will store current brightness/contrast/color data into Standard.
- Apr Threshold Adjust: This is used to increase the contrast of pictures with low contrast and avoid clipping at RGB output of picture with high peak amplitudes. Change its value to get perfect contrast quality of picture.
- E-W Correction And H-Wide Adjust For Pure Flat CRT: Receive cross pattern. Adjust picture in Standard mode use PP key. Adjust VR801 to set picture's wide. Adjust VR802 to get a good linear pattern. Adjust VR801 to set picture's wide if it is changed after adjust VR802.
Design for ST92195 and Set Options:
The manual details how to operate the ST92195 microprocessor and configure various set options using the factory mode. This includes settings for:
- AGC Gain: Usually set to zero.
- Option 1: Controls features like LOGO display, Inter Carrier/QSS (NICAM), High Gain Tuner, X-Ray protection, Cut Off Loop, and Inter Carrier/QSS without NICAM.
- Option 2: Manages Coring when Peaking, Auto Flesh when NTSC, Black Stretch, APR, Color +6Db, and Language OSD (Two Language/One Language OSD).
- Option 3: Configures ICs like TDA7449/TDA7439, TDA1905/TDA7496, Manual/Auto Cutoff, SECAM LL' for France, and PIF Overmodulation. It also specifies MCU's MUTE pin output voltage selection based on TDA1905 or TDA7496.
- Option 4: Manages AV inputs (AV1, AV2), SVHS, and RGB.
- Option 5 (Teletext): Used to select teletext languages for different regions and enables the remote controller to change Run_Time_Mode_Choice.
- HPOS OSD/VPOS OSD: Adjusts the horizontal and vertical position of the On-Screen Display.
- HPOS TXT/VPOS TXT: Adjusts the horizontal and vertical position of teletext characters.
- LOGO Set: Instructions for setting the LOGO, including selecting characters and their number.
The manual provides default values for white balance adjustments, including Red Gain (32), DC Red (063), Green Gain (32), DC Gain (063), Blue Gain (32), DC Blue (063), Apr Threshold (10), and LOGO (6). These values are automatically initialized, but IC002 (EEPROM) must be re-adjusted for factory use. If a blank EEPROM is used, it will be initialized with default values.
Procedure for 3S10 Chassis (Only for reference):
The manual outlines a two-stage procedure for chassis setup:
- Touch up line: Includes B+ voltage adjust, VCO adjust, and IF trap adjust for NTSC-M system. This stage focuses on achieving perfect NTSC-M picture quality without SIF signal disturbance.
- Final Assembly Line: Covers Screen and Focus voltage adjust, TAGC adjust, White balance adjust, H/V central and V Amp 50 adjust for PAL, Bright Min adjust, and V AMP 60 and Sub Tint for NTSC.
The circuit diagram, located on page 13, provides a visual representation of the television's internal electronic components and their interconnections, essential for detailed troubleshooting and repair.
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