NTDDVD01 I TECHNICAL TRAINING MANUAL DVD VIDEO PLAYER SD-3006 SD-2006 TOSHIBA AMERICA CONSUMER PRODUCTS, INC. NATIONAL SERVICE DIVISION TRAINING DEPARTMENT 1420-B TOSHIBA DRIVE LEBANON, TENNESSEE 37087 PHONE: (615) 449-2360 FAX: (615) 444-7520 www.toshiba.com/tacp �1997 4. BLOCK DIAGRAMS ...................17 Contents 4-1. Main Board. ......................................17 4-2. RF Amp and Tracking......................18 4-3. Servo. .................................................19 1. BIRTH OF DVD..............................3 4-4. Demodulation, Error Correction, and 1-1. Background .........................................3 Decryption. ........................................20 1-2. Specifications of the DVD Player ......3 4-5. MPEG2 Decoder ...............................21 1-3. Disc Type .............................................3 4-6. Video Processor ................................22 1-4. Disc Structure .....................................4 4-7. Video Processing ...............................23 1-5. Disc Capacity ......................................4 4-8. Audio Processing ..............................24 1-6. DVD Memory Capacity .....................4 4-9. System Control. ................................25 1-7. Recording Sequence and Direction ...5 5. CIRCUIT DESCRIPTIONS .........26 1-8. Two Bonded Discs...............................5 5-1. Overview ...........................................26 2. FEATURES OF DVD .....................6 5-2. Power Supply ....................................27 2-1. DVD is not a Digital Video Disc.........6 5-3. Front Panel Display ..........................29 2-2. Very Large Capacity ..........................6 2-3. Enabling Technology ..........................6 2-4. High Picture Quality ..........................8 2-5. Digital Sound ......................................9 2-6. Advanced Functions of DVD .............9 3. DVD TECHNICAL POINTS .......12 3-1. Compatible Disc................................12 3-2. Title, Chapter, and Track.................13 3-3. Video Compression...........................14 3-4. Tracking and Focus Errors..............15 3-5. Reading a 2-layer Disc .....................15 3-6. 1-Track Lens Kick (Return) ............16 3-7. Laser PU ...........................................16 2 1-3. Disc Type 1. BIRTH OF DVD There are four types of discs. 1-1. Background 1-3-1. Single-layer, Single-side Disc. Everyday, we enjoy entertainment through various media, 0.6mm such as movies, television, radio, newspapers, and magazines. A computer, which has been used mainly for business, is 0.6mm coming closer to becoming a tool in our everyday lives. We are surrounded by a host of visual images, photographs, sounds, and characters. TOSHIBA has sought out the means which enables us to record as much of this information as possible, in the highest 1-3-2. Single-layer, Double-side Disc quality possible. in a form as compact as possible, and is Side B easy to handle and enjoy. For this purpose, we have developed many unique 0.6mm technologies, through discussion with computer profession- als, as well as the studio staffs in Hollywood, the home of the 0.6mm film industry in the U.S.A. As a result, we have developed DVD , a digital versatile Side A disc for the next generation, having the memory capacity of 7 times that of a CD on a single side of the disc. 1-3-3. Double-layer, Single-side Disc. 1-2. Specifications of the DVD Player 0.6mm Table 1 0.6mm Disc diameter: 120 mm Disc thickness: 1.2 mm, 0.6 mm x 2 (stuck) 2nd layer 1st layer Semiconductor laser 650 nm wave length: Lens (NA): 0.6 0.4 ~ 1. 87 �m (Single-layer)/ Pit length: 0.44 ~2.05 �m (Double-layer) 1-3-4. Double-layer, Double-side Disc. Track pitch: 0.74 �m 1st layer Sector placement: CLV (Constant Linear Velocity) 2nd layer Modulation: 8/16 modulation RS-PC (Read Solomon Product Error correction: Code) 0.6mm 1) 4.7 GB (Single-side single-layer) 0.6mm 2) 8.5 GB (Single-side double-layer) Memory capacity: 3) 9.4 GB 2nd layer 1st layer (Double-side single-layer) 4) 17 GB (Double-side double-layer) 3 1-4. Disc Structure The 1st layer (semitransparent reflection film) of the dou- ble-layer disc does not reflect if a laser beam focus is not correct. 1-4-1. Single-layer, Double-side Disc Side B (standard reflection film) 0.6mm Bonded layer Side A (standard reflection film) 0.6mm 1-4-2. Double-layer Single-side Disc 2nd layer (standard reflection film) 0.6mm Bonded layer (transparent) 1st layer (semi-transparent reflection film) 0.6mm 1-5. Disc Capacity Table 2 Giga bytes (G Bytes) Single-layer Double-layer Single-layer Double-layer single-side single-side double-side double-side 12 cm 4.7 8.5 9.4 17 8 cm 1.4 2.6 2.9 5.3 Data rate required: 1-6. Calculation of DVD Memory Capacity Sub Conditions: Video Audio Total total 1. Average video data rate is 3.5 Mbps (bit per second) 3,500 k + (384 k x 3) + (19 k) = 4,692 kbps or more. (The compression rate varies depending on video Disc capacity required: data.) (8 bits = 1 Byte) Data rate Recording time Memory capacity 2. Sound is Dolby AC-3, 5.1 channel digital surround. 4.692 kbps x (133 x 60) sec � 8 = 4,680.270 kBytes 3. Three dubbing languages plus four subtitle lan- guages. 4. Record 133 minutes on one side of the single-layer Recording for 133 minutes in one side of the single- single-side disc. layer single-side disc requires 4.7 giga bytes. 4 1-7. Disc Recording Sequence and Direction There are three recording sequences and directions. 1-7-1. Single-layer disc Disc center Lead-in area Data area Lead-out area 1-7-2. Double-layer disc (A) 2 Disc center Lead-in area Data area Lead-out area 1 1-7-3. Double-layer disc (B) 2 Lead-out area Disc center Lead-in area Middle area Data area 1 1-8. Two Bonded Discs The DVD disc consists of two 0.6 mm bonded discs, suitable for reading a data signal recorded in high density. Since the disc is thinner, the obstacle in the optical pickup and in the pit on the disc are smaller, enabling accurate reading. By bonding discs of the same material back to back, the flatness of the disc is increased, suppressing warp caused by heat and humidity by 1.2 mm compared with a single-plate disc, greatly enhancing reliability. Warp caused by heat or humidity 0.6mm 1.2mm 0.6mm DVD (stuck) CD (single-plate) 5 2-3. Enabling Technology 2. FEATURES OF DVD 2-3-1. Large Recording Capacity 2-1. DVD is not a Digital Video Disc " Track pitch is reduced to half that of a CD to make the "DVD" has been known as digital video disc, as well digital track length long. versatile disc. Actually, DVD sets the standard for the next " Pits are made fine (half that of a CD) to increase the generation of high density optical disc. The abbreviation for volume of data to be recorded. digital video disc does not encompass all the capability of " The fine pit requires the laser beam spot (focus) to be DVD. DVD is employed as the name for the standard it sets. small. " To make the spot small, the laser beam wavelength is made short and the number of aperture (NA) of the ob- 2-2. Very Large Capacity jective lens is made large. A DVD disc is the same size as a 12 cm CD, but it can record With the larger NA, the influence of laser beam aberrations 4.7 Giga Bytes (GB) on one side, which is equivalent to about due to the protective film (the transparent plastic part) 7 CDs. It can record one whole movie of 133 minutes with increases and the beam spot (focus) blurs with respect to theater quality picture and sound. This is the capacity of the the disc inclination or the spot displaces widely from the single-side single-layer disc. The single-side double-layer pit, decreasing the signal read accuracy and increasing the disc has a capacity of 8.5 GB. The single-layer double-side noise element. disc has a capacity of 9.4 GB. The double-layer double-side To minimize the influence of laser beam aberrations, the disc has the capacity of 17 GB maximum. disc is made thin (0.6 mm or half the thickness of a CD). The memory capacity of the disc is determined by the in- To provide compatibility with a CD, the disc is made by formation time and data per second (data rate). In a CD, the bonding two 0.6 mm discs. The two-disc structure increases quantized bit number is 16 bits, the sampling frequency is planarity of the disc, resulting in improved signal read 44.1 kHz and the number of channels is two. Therefore, the accuracy, as well better resistance to warpage. data volume of a CD is 16 x 44.1 kHz x 2 = approximately 1,411 k(bit/sec) = 1.411 M(bit/sec). The DVD disc has 4.7 GB or 37.6 giga bits (4.7 GB x 8) of memory capacity in one side. A CD records 74 minutes maximum. Therefore the DVD disc records 7 hours and 24 minutes (37.6 x 1000 � 1.411 = 26.648 sec.) with the same quality sound as a CD. DVD data capacity DVD recording time CD LD (Approximate amount) DVD DVD 4.7 688 133 60 minutes minutes GB MB (single-side) Approx. 7 times x 6.8 pcs. (single-side) Approx. 2.2 times x 2.2 (side) of CD of CD 6 2-3-2. Comparing DVD with CD Table 3 Item CD DVD DVD (CD) * Track pitch 1.60 �m 0.74 �m 1.60 �m Minimum pit 0.87 �m 0.40 �m 0.87 �m 780 nm (Infrared Laser beam wavelength 650 nm (Red) 650 nm (Red) ray) Number of objective aperture 0.45 0.6 0.35 Laser spot 1.8 �m 1.0 �m 1.8 �m * CD mode of DVD 2-3-3. Small Laser Beam Spot (Focus) 2-3-4. Long Track Length The size of the laser beam spot, ł, is smaller because the Laser beam spot laser wavelength is shorter and the NA is larger, as determined by the equation below. laser wavelength ł = NA 0.74 �m track pitch Where, NA (Number of aperture) = 0.6 (DVD) = 0.35 (CD, DVD) laser beam wavelength = 650 nano-meter Minimum pit 650 nm DVD ł = = Approx. 1 micro-meter 0.4 �m 0.6 650 nm CD (DVD) ł = = Approx. 1.8 micro-meter 0.35 2-3-5. Thin Disc The thin disc minimizes blur (disturbance) in the focus and NA indicates brightness of the lens. It increases as the focal shift of the beam spot against the disc inclination. distance is decreased, and the diameter is increased, as determined by the following equation: Laser beam spot f a CD DVD NA= a f Disc Objective lens 7 2-3-6. Long Play Time 2-4. High Picture Quality The increased capacity, due to the longer track and finer pit, still won't allow the recording of a complete movie on 2-4-1. High Resolution one side (one layer) of a 12 cm DVD without compression. The picture quality of DVD is 500 lines of horizontal reso- The digital video data must be compressed to realize a full lution, a great improvement over current media, such as the 133 minutes on a one side-single layer disc. Laser Disc at 430 lines. The technique of compressing video data was developed With the high resolution and high picture quality, the image by the Moving Picture image coding Experts Group (MPEG) contour is clear and sharp and even a dark scene can be and is the worldwide standard. played with perspective and with minimum noise. MPEG1 (fixed bit rate system) was standardized first and was applied to video CD, such as used for KARAOKE and 2-4-2. Applicable to a Wide Screen CD-ROM. When DVD is applied to a wide screen TV, it can play fine MPEG2 (variable bit rate system) was standardized next and beautiful images free from degradation even when in and makes DVD possible. Since video images contain zoom (magnifying images vertically/horizontally). redundant information from one frame to the next, MPEG2 compresses data by predicting motion that occurs from one frame of video to the next. Motion vectors and background information are recorded rather than entire video frames. Horizontal 430 lines 240 lines 500 resolution lines 400 lines/240 lines DVD S-VHS video/VHS video LD Video CD Recording Digital (MPEG2) Analog Analog Digital (MPEG1) method Comparing the horizontal resolution and recording method of DVD with current media Full mode Zoom mode Video play on a wide screen TV. Picture is DVD play on a wide screen TV. High picture degraded. quality of a wide screen TV can be realized. Applicable to a Wide Screen 8 2-5. Digital Sound 2-6. Advanced Functions of DVD The DVD delivers a super digital sound, exceeding that of a Many advanced functions can be recorded on a DVD and CD. are determined by the individual software makers. Each DVD disc may have different functions. Only the recorded 2-5-1. Recording a Dynamic Range of 144 dB functions on a particular disc can be played back. Utilizing its large capacity, DVD realizes ultra Hi-Fi digital audio with a dynamic range of 144 dB, based on a high 2-6-1. Multilanguage sampling rate of 96 kHz and 24 bits resolution. (1) Selection of voice DVD range A maximum of eight audio streams is available for a 146 dB (24 bit) DVD video. These are digital signal paths, not "chan- Natural sound nels." Up to eight languages, including the original lan- guage, can be recorded. It is also possible to record all CD range 96 dB of the Dolby AC-3 5.1 channels in the eight streams. (16 bit) For example, a 5.1 channel in English in the first stream, French in the 2nd stream, and non-compressed linear PCM in the 3rd stream. As the amount of sound data increases, the recording time decreases accordingly. To increase the recording time, producers may reduce the number of streams or select Dolby AC-3 2 channel instead of non-compressed Band frequency 20 kHz 40 kHz linear PCM. Dynamic ranges of DVD and CD (2) Selection of subtitles Utilizing 32 channels of sub image, up to 32 subtitle languages can be superimposed. Japanese, English or 2-5-2. Sound Effects Like a Movie Theater French can be independently recorded into each chan- nel. Dolby AC 3 digital sound is adopted. AC 3 consists of 5.1 channels; Front left, center, and right, Rear left and right, and a sub woofer (Low frequency effects). An AC 3 decoder and 5.1 channel amplifier and speaker system allow for playback of the full digital sound. 9 Dynamic range 2-6-2. Special Modes (1) Multi-angle function Using two or more cameras, the images of concerts, sporting events, dramas, or other events can be recorded at a maximum of nine angles. With a DVD disc recorded in this way, a viewer can select a desired angle. (3) Multistory function If two or more branch stories have been recorded for a (2) Parental lock function main story, it is possible to select a branch story, call the Utilizing the multistory function, parents can lock out menu screen at each branch, and select a desired branch the violence, sex or other scenes, they don t want their and change the main story. children to view. Parents can: A. Main and sub story function 1) Cut these scenes. This function enables the viewer to play a main story 2) Replace these scenes by the other scenes, if pre- with another hero or heroine by selecting a sub story. pared previously. B. Multi-version function 3) Disable playing the disc itself. This function enables the viewer to play two or more versions, such as a theater version, complete version, " The lock function can be set at the lock level. and director s cut version. " Nine lock levels are available and are used based on C. Highlight scene scan function the regulations in each country. This function enables the viewer to play scenes of fa- " If scenes, which are not wanted to be viewed by chil- vorite stars or music. dren, are recorded on a DVD disc, a certain lock level is set in the disc. " Once a lock level has been set or selected in the DVD video player, the system will not play a disc or scenes from a higher lock level setting. Main story and sub story 10 D. Branching story function (5) Multi-aspect function (simple interactive function) This function makes a DVD disc compatible with any This function enables the viewer to develop a story type of TV. Since the squeeze method is employed to interactively, similar to a so-called roll playing game. record wide screen images, compressed to a 4:3 ratio, For example, it is possible to change the development the width is simply returned in the full mode when the of a story by selecting the actions of characters from disc is played on a wide screen TV. With 4:3 large screen a menu. or direct view TVs , high picture quality is ensured by selecting the letter box to reduce the height, or the pan Branching story & scan to cut the side portions to fit the 4:3 ratio. In many cases, current wide screen images are broad- cast or recorded with the black bars at top and bottom for the 4:3 screen. Thus, when viewed or played back on a wide screen TV, the black bars are expelled by zooming the screen to realize the wide screen image. In this case, scanning lines are expelled out of the screen and are reduced from 425 to 360, causing degradation in picture quality. On DVD, the squeeze recording method solves this problem and allows playback on a wide screen TV with the normal number of scanning lines. " The recording methods and whether the letter box/ pan & scan can be used, depends on the DVD disc manufacturer. They are not always available on all (4) Playing the multistory DVD discs. The multistory functions are possible only for discs re- corded with this feature. Since the contents of a DVD disc are determined by the disc producer, a variety of different discs may be marketed. Because a specific ex- planation of the operation of the multistory features is not possible, the owner's manual only instructs the user to "Follow the procedure displayed on the screen or DVD package." Wide screen TV (full mode) Direct output Wide image Squeeze recording DVD player 4 : 3 TV Disc Converted output Letter box conversion Pan & scan conversion Multi-aspect function 11 3. DVD TECHNICAL POINTS (MODEL SD-3006, SD-2006) 3-1. Compatible Disc 3-1-1. Types of Discs Playable with the DVD Video Player 3-1-2. Recognition (Area Code) of DVD Video Disc The area code is globally set for Japan, USA/Canada, Asia, The DVD video player is a play only device. It can play Europe, and other areas and countries. This area code is DVD video discs and music CDs as shown below. recognized in some DVD discs. This is the result of the Table 4 strategies of the software makers. Essentially, the DVD discs of newly released movies and music CDs are not playable other than in those areas that are authorized. Mark (logo) Contents Size Max play time Therefore, if you play a DVD video disc purchased in a Single-side disc foreign country using a DVD player sold in the U.S.A., or if About 4 hours you play a business-use disc, the message, The area code 12 cm Double-side disc is wrong and the disc cannot be played may appear on the About 8 hours Sound + video DVD video screen. (moving picture) disk VIDEO TM Single-side disc About 80 minutes 8 cm 3-1-3. Copy Prevention Double-side disc About 160 minutes It is forbidden by law to copy, broadcast, show, broadcast 12 cm 74 minutes on cable, play in public, and rent copyrighted material Music CD Sound 8 cm without permission. 20 minutes (Single CD) DVD video discs are copy protected, and any recordings made from these discs will be distorted. Note: " Other discs cannot be played. 3-1-4. Wide World of DVD " This player conforms to the NTSC TV system, and is Since video, sound, and data file formats are unified for not compatible with discs made for the other TV sys- DVD, it eliminates the borders between television, audio, tems (PAL, SECAM). and computer applications. CD Audio CD CD-ROM DVD DVD-ROM DVD- Rewritable DVD Video Civil apparatus (TV environment) Computer application 12 3-2. Title, Chapter, and Track A DVD video disc is generally divided by title and is fur- The titles, chapters, and tracks are numbered. These numbers ther divided into chapters . On the other hand, a music are not recorded on some discs. CD is divided into tracks . Example: DVD video disc DVD video disc Title 1 Title 2 Chapter 1 Chapter 1 Chapter 1 Chapter 1 Chapter 1 Example: Music CD Music CD Truck 1 Truck 2 Truck 3 Truck 4 Truck 5 Title: DVD video disc contents are divided into several parts. This is equivalent to a story or a collection of short stories. Chapter: The title contents are further divided into scenes or tunes. This is equivalent to a chapter of a book. Track: Music CDs are divided into songs. 13 3-3. Video Compression MPEG2 compresses data to about 1/40, and, along with other techniques achieves a picture quality higher than LD. Though the recording capacity of a DVD disc is 7 times greater than a CD, only about 4 minutes of an NTSC TV * MPEG is the Moving Picture Experts Group, the com- image can be recorded as a full digital file. pression technique working group, part of the ISO/IEC joint technical committee. ISO is the International Standardization Investigations into data compression techniques began in Organization and IEC is the International Electric Standard the 1960 s, yielding such standards as JPEG, MPEG1, and Conference. MPEG2. MPEG1 was adopted for video CD (music CDs used to ac- company live singing). MPEG1 compresses data to 1/100, enabling it to record a maximum of 74 minutes of video, but, the picture quality is inferior to that of a Laser Disc. Video compression system MPEG2 MPEG1 (apparatus adopting this system) (DVD) (Video CD) 720 x 480 pixel 352 x 240 pixel Main video resolution 1/60 sec 1/30 sec Frame rate 60 images per second 30 images per second Data transmission rate 1 ~ 10 Mbit/sec (variable) 1.15 Mbit/sec (fixed) Average compression rate Approx. 1/40 Approx. 1/100 Picture quality Equivalent to VH Higher than LD Comparing the video of MPEG2 with MREG1 3-3-1. Concept of MPEG2 Generally, the system is based on the principal that moving The MPEG2 compression technique consists of about 20 images contain redundant information from one frame of items, including a variable data transfer rate from 10 Mbps video to the next; the background stays the same for many for a complex or quick moving picture to 1 Mbps for a simple frames at a time. Compression is accomplished by predicting or nearly still picture. The average data transfer rate is 3.5 motion that occurs from one frame to the next. Motion Mbps. vectors and background information is recorded, rather than entire video frames. MPEG2 decoding reconstructs the video frames. 14 3-4-3. Detecting a Focus Error (Astigmatic Method) 3-4. Detection of Tracking and Focus Errors An error signal is detected by changes in the beam shape. 3-4-1. Detecting a Tracking Error in CD Mode This beam is formed by the sensor lens of the laser PU, and (3-Beam Mode) as the distance between the objective lens and the disc surface The auxiliary beams (E and F) are made by the diffraction varies, the beam shape changes. The shape of the beam from grating of the laser PU and are displaced from the main the sensor lens, applied to the PD, is circular if the beam beam as shown below. The auxiliary beams are displaced focus is adjusted to the surface of the disc. If it is out of ahead of and behind the main beam to prevent crosstalk focus, it spreads in the direction of A + C or B + D of the PD, between tracks or signal interference between auxiliary like an ellipse, as shown below. The corresponding ąDC beams. Condition 2 below is the correct condition; the voltage is the focus error signal. main beam is located at the middle of the track and the Sensor lens auxiliary beams A and B ride a little over the track by the Beam spreading in the directions same amount on either side, so the outputs of E and F of A and C become equivalant and the output of the error circuit Beam spreading becomes zero. If the auxiliary beams are offset to either in the directions side, as shown in 1 or 3, the outputs of E and F are no of B and D longer equal and the error signal becomes positive for A A A B D B D B D condition 1 and negative for condition 3. C C C Distance from A (E) Near Optimum Far the lens to the + disc � + A + C Focus B (F) error signal � B + D 1 = + 2 = 0 12 3 3 = � 3-4-2. Detecting a Tracking Error in DVD Mode 3-5. Reading a 2-layer Disc (Verified DPD) Some DVD video discs have two layers of reflective film on one side. The upper layer is a standard reflective film The phase difference system improves stability against (2nd layer), and the lower layer is a semi-transparent damaged discs. The phases of the one-beam PD (Photo reflective film (1st layer). Detector) outputs A + C and B + D are compared in the DP With a single-layer reflective film, signals are read in the (Phase Detector), and a tracking error signal is generated. same manner as with audio CDs. With double-layer discs, a When the beam is correctly located, as shown in drawing 2 laser beam must pass through the lower reflective film to below, the phases of A + C and B + D are the same, and the read the the upper reflective film. tracking error output is zero. However, if the beam is offset, The lower film is made semi-transparent (reflection rate of as shown in drawing1 or 3, a phase difference occurs and a + 30%) and the beam focus is adjusted to the upper film. or - DC voltage is produced as an error signal. Bonded layer (transparent) Array of PD Pit 2nd layer (standard reflection film) B A C D Beam 0.6mm 1 2 3 Tracking error output B+D B + D 0.6mm � PD + A+C A + C Phase Delayed Same Advanced 1st layer (semi-transparent reflection film) 15 3-6. 1-Track Lens Kick (Return) 3-7-2. Laser PU Structure Data pickup for an audio CD is performed at a constant rate The construction of the PU is shown below. along the track of a disc, because the data is recorded at a fixed bit rate in the track. In DVD, data is recorded at a Disc The working lens is detected by variable bit rate and the amount of data is not constant in receiving the laser beam reflected Objective from the mirror provided under the each track. Thus, the readout information (by frames) from objective of CD using a Mirror the laser PU is stored in memory prior to playing on the screen photosensor. at the correct frame rate. Since the memory capacity is Photosensor limited, it soon overflows. When the amount of data in the Collimator lens (used to parallel the beam) memory reaches a certain level, the objective lens is returned by one track, and held in the pause mode until the memory Deflection beam splitter Diffraction Laser volume decreases. This keeps the memory controlled at about grating diode 90% of capacity. Memory information is given priority. Read from a disk Reflector and memorized. Same time Sensor lens d e f g h i j k l /4 plate Held in pause Memory access Time mode until Photodetector a b c d e 3-7-3. Cleaning the laser PU objective Called from the memory and played on the The objective lens becomes dirty over time and should be TV screen (the access time is constant). cleaned periodically. As the lens surface gets dirtier, the intensity of the laser beam decreases, causing playback failures. 3-7. Laser PU " If the RF level is not restored to the correct level after 3-8-1. Two Lenses cleaning the objective lens, the collimator lens probably DVD can play an audio CD is one of the conditions of the needs cleaning. DVD format. The methods of reading DVD and CD signals (1) Cleaning the Objective Lens is the same, but the pit size and disc thicknesses are different. 1 Moisten a cotton swab with pure alcohol (not rubbing The same lens can not read both. alcohol) and wipe the lens outward 3 to 4 times, just To solve this problem, the DVD/CD 2 lens switching system like drawing a circle. or the two-focus system (which uses a holographic lens at 2 Repeat at least two more times, using a clean cotton the center of the main lens, so that the CD signal is read at swab each time. the middle of the lens and the DVD signal is read with the whole lens) is used. The SD-3006 uses the two-lens system. (2) Laser PU Performance The large lens is selected when playing a DVD disc, and the If proper performance is not regained after cleaning the small lens is selected to play a CD. objective lens and internal optics, the laser diode may be near the end of its useful life. Lens case The lifetime of the laser diode depends on environ- Lens support axis mental conditions, such as temperature and humidity, but is usually about 5,000 to 10,000 hours. Rotation direction Lens for CD Lens for DVD 16 4. BLOCK DIAGRAMS 4-1. Main Board. Refer to Diagram 4-1. Main Board. Except for the System Control block, video and audio data flow in a linear progression through each of the blocks, until The main board of the DVD player can be segmented into the data is converted to the desired format, and exits the player. eight distinct functional blocks: 1. RF Amp and Tracking. 2. Servo. 3. Demodulation, Error Correction, and Decryption. 4. MPEG 2 Decoder 5. Video Processor 6. Video Processing 7. Audio Processing 8. System Control. RF AMP DEMOD SERVO & ERROR CORR TRACKING DECRYPTION MPEG2 VIDEO DECODER PROCESSOR SYSTEM CONTROL VIDEO VIDEO OUT PROCESSING AUDIO AUDIO OUT PROCESSING Diagram 4-1. Main Board 17 4-2. RF Amp and Tracking. GO TO MAIN BLOCK Refer to Diagram 4-2. RF Amp and Tracking. The laser pickup develops tracking error and focus error signals and sends them to IC501 and IC502, via pins 10 IC502 develops the laser drive signal and sends it to the laser through 15 of CN501. There are two types of tracking error pickup via pin 7 of CN501. Once the disc starts spinning, signals developed. The DVD player functions as a single the laser pickup sends two differential RF signals to the beam system for DVD discs, and a three beam system for equalization circuits in IC502 via pins 16 and 17 of CN501. CD audio discs. Error signals A, B, C, and D are applied to the offset comparator in IC501 to develop the DVD tracking If a DVD disc is playing, the RF eye pattern signal is output error signal. The DVD tracking error signal is phase detected, on pin 34 and can be monitored at test point 502. output on pin 14, and applied to a switch in IC502, via pin 8. Error signals E and F are generated by a CD audio disc and If a CD audio disc is playing, a lower frequency eye pattern applied to the CD tracking error comparator in IC502. The signal is output on pin 39 and can be monitored at test point resulting CD tracking error signal is also applied to the switch. 501. The switch selects the proper tracking error signal, TE, and outputs it on pin 21. TE can be monitored at test point 507. Signals A, B, C, and D are applied to the focus detector circuit in IC502 to develop the focus error signal, FE. FE is output on pin 27, and can be monitored at test point 505. TE IC501 DVD-TE A, B, PINS DVD TE 10 - 15 C, & D PHASE OFFSET 14 DET COMP LASER PICKUP 8 TP507 E & F 21 LASER CD TE COMP TE FOCUS TP505 27 PICKUP FOCUS DET FE TRACKING A, B, TP502 7 COIL LASER 34 C, & D DVD EQ DVD RF DRIVE TP501 39 CD RF CD EQ PINS RF 16 & 17 IC502 RF AMP CN501 Diagram 4-2. RF Amp and Tracking. 18 4-3. Servo. GO TO MAIN BLOCK Refer to Diagram 4-3. Servo. Feed motor drive information from the system control, IC601, The servo block is responsible for driving and controlling is sent to the servo control in IC503 via an I/O bus. The the disc motor, the feed motor, and the focus and tracking servo control develops the feed motor drive signal and outputs coils. When a disc is inserted in the player, several events it on pin 53. This signal is amplified in IC505 and sent to the occur before the RF signals or tracking signals are developed. feed motor, via pins 1 and 2 of CN502. Two hall switches First, the feed motor pulls the laser slide assembly toward monitor the rotation of the feed motor and send signals to the disc motor and stops when the disc is in the correct IC509, via pins 5 through 8 of CN502. This information is position. Then, the focus coil pushes the objective lens up processed in IC509, and sent back to the system control IC, and down in an attempt to achieve focus. During this startup which monitors the speed and position of the feed motor. process, the focus and tracking error signals are developed and applied to the servo control circuit in IC503, via pins 43 IC503 also processes the CD RF signal on pin 38. The signal and 46. The servo control circuit processes the focus and is demodulated, error corrected, and sent to IC904, via pin 9. tracking error signals, and develops the focus and tracking This signal is also monitored by the servo control to develop drive signals, output on pins 48 and 49. The focus and the CD CLV error signal, output on pin 55. tracking coils must be rotated 90 degrees to change the objective lens for an audio CD. The focus and tracking drive The CD CLV signal is applied to the disc motor drive, IC510, signals are switched for the proper orientation in IC506. The pin 21. The disc motor drive keeps the disc motor running at drive signals are amplified in IC505 and applied to the focus the proper speed. IC510 sends three drive signals to the disc and tracking coils, via pins 1, 2, 3, and 4 of CN501. motor via pins 17, 18, and 19 of CN502 . A series of hall switches in the disc motor sends feedback signals to IC510, via pina 9 through 16 of CN502. CN502 LASER IC509 FEED 10 PUTAC F/T SPEED DISC TO IC601 MOTOR PINS COIL DET MOTOR 5 - 8 CN501 CN502 2 & 3 1 & 4 17 - 19 FROM FROM IC502 CN502 1 & 2 IC601 9 - 16 FE TE CD RF IC505 38 43 46 90 - 93 DRIVE DEMOD 19 25 10 53 14 15 FEED PLL CD DRIVE BACK 49 IC506 DATA 9 CORR 1 SERVO TRACKING TO FT CONTROL 48 IC904 SWITCH IC510 IC503 FOCUS 13 DISC SERVO MOTOR 55 21 CD CLV DVD CLV DRIVE FROM IC201 Diagram 4-3. Servo. 19 4-4. Demodulation, Error Correction, and Decryption. GO TO MAIN BLOCK Refer to Diagram 4-4. Demodulation, Error Correction, and Once the signal is demodulated, it is error corrected and sent Decryption. to Data Processor 2, IC207. Data Processor 2 detects the region code in the DVD signal, and if it matches the region code of the player, the signal is processed, and the MPEG2 The DVD RF signal from IC503 is applied to the data slicer Data is sent to IC304, the MPEG2 Decoder. However, if the in Data Processor 1, IC207, via pin 50. The data is processed region code is incompatible, the disc will not play, and the and applied to the phase locked loop (PLL), so the incoming region code error message is displayed on the screen instead. data can be locked to the timing of the processor. Since the The DVD signal from the PLL circuit is also applied to the bit rate of the DVD data can vary, the data is stored in the 4 CLV drive circuit, to produce the DVD CLV error signal. meg DRAM, IC202, then sent to the 8/16 demodulator as This error signal is sent to pin 21 of IC510 to keep the disc needed. motor running at the proper speed. DVD RF FROM DATA SLICER 50 IC502 IC202 PLL 4 MEG DRAM 8/16 DEMOD IC207 DATA DVD CLV ERROR CLV PROCESSOR 2 TO IC510 CORRECTION 54 DECRYPTION IC207 DATA PROCESSOR 1 DEMOD & ERROR MPEG2 DATA CORRECTION TO IC304 Diagram 4-4. Demodulation, Error Correction, and Decryption. 20 4-5. MPEG2 Decoder GO TO MAIN BLOCK Refer to Diagram 4-5. MPEG2 Decoder. The parallel DVD data from IC207 is applied to the Program Stream Decoder in the MPEG2 decoder, IC304, where it is decoded into audio and video data. During the decoding process, the data is stored in the 16 meg DRAM, IC202, via the memory interface. The decoded audio and video data are sent to IC301 via the video interface. IC304 PROGRAM MPEG2 MPEG2 DATA STREAM FROM IC207 DECODER DECODER VIDEO & AUDIO MEMORY VIDEO DATA INTERFACE INTERFACE TO IC301 IC202 16 MEG DRAM Diagram 4-5. MPEG2 Decoder. 21 4-6. Video Processor GO TO MAIN BLOCK Refer to Diagram 4-6. Video Processor. The Video Processor, IC301, processes both the audio and the video data from IC304. Audio is processed by the system decoder and sent to IC902. Video is processed by the mixer and sent to IC307. In the model SD3006, the color difference signals, Cb and Cr, are produced by the mixer and output on pins 115 and 117. All On Screen Display (OSD) information is produced by IC303 and applied to the mixer. Sub titles, extracted from the DVD data, are processed by the Sub Title Processor, in conjunction with the 1 meg DRAM, IC302. The sub title data is sent to the mixer to be combined with the video signal. VIDEO & AUDIO AUDIO DATA SYSTEM DATA TO IC902 DECODER FROM IC304 VIDEO DATA TO IC307 MIXER IC303 Cr (R-Y) 117 Cb (B-Y) OSD 115 IC301 IC302 SUB TITLE VIDEO 1 MEG PROCESSOR PROCESSOR DRAM Diagram 4-6. Video Processor. 22 4-7. Video Processing GO TO MAIN BLOCK Refer to Diagram 4-7. Video Processing. Video data from IC301 is applied to the Macrovision Copyguard, IC307. The data is then applied to the video Digital to Analog Converter (DAC), IC306. Analog luminance (Y) is output on pin 46, chrominance (C) is output on pin 43, and composite video (CV) is output on pin 40. In model SD2006, the switches (SW) are fixed to output only the Y, C, and CV. However, in model SD3006, the switches are controlled by the Video Select Switch, on the back of the player. In one position, the outputs are the same as for the SD2006. When the Video Select Switch is in the other position, the player outputs Cb, Cr, and Y. VIDEO DATA FROM IC301 IC307 MACROVISION COPYGUARD 46 Y LPF SW AMP SW Y IC306 43 VIDEO C AMP SW SW C LPF DAC 40 CV SW LPF AMP SW CV Cb Cb SD3006 Cr Cr ONLY FROM VIDEO SELECT SWITCH Y SD3006 ONLY Diagram 4-7. Video Processing. 23 4-8. Audio Processing GO TO MAIN BLOCK If the audio selector switch on the back of the player is in the Refer to Diagram 4-8. Audio Processing. ANALOG/PCM position, analog audio data are output on pin 11, and PCM audio data are encoded and output on pin Parallel audio data from IC301 is applied to the buffer in the 17. Analog audio data is converted to right and left analog parallel to serial converter, IC902. The 4 meg DRAM, IC903, signals by the audio DAC, IC905, and output on pins 17 and stores the data as it is converted into serial data. The serial 18. However, if the audio selector switch is in the AC3/ audio data is then output on pin 44 to the AC3 decoder, IC901. ANALOG OFF position, no analog data is output on pin 11, The audio data is then applied to the data I/O in the audio but AC3 audio data is encoded and output on pin 17. system processor, IC904. The Data I/O selects either DVD audio, or CD audio, depending on the type of disc being played. IC901 IC903 AC3 4 MEG CD DATA DECODER FROM IC503 DRAM 18 LPF ANALOG 13 52 IC905 AMP LEFT 44 52 54 AUDIO 17 LPF DAC ANALOG 8 AMP RIGHT DATA I/O 11 P/S BUFFER 17 DIGITAL DIGITAL IC902 P/S ENCODER AC3/PCM CONV IC904 AUDIO AUDIO DATA SYSTEM FROM IC301 PRO Diagram 4-8. Audio Processing. 24 4-9. System Control. GO TO MAIN BLOCK Refer to Diagram 4-9. System Control. All functions of the DVD player are controlled by the System Control. This consists of the main microcomputer, IC601; the SRAM, IC604; the DRAM, IC611; and the EEPROM, IC605. When the player is plugged in, the main microcomputer is reset by the DSPRST signal on pin 67. The microcomputer stays powered by the EVER +5Vdc on pin 25. Its timing is derived from the 16 Mhz crystal, X601, on pins 27 and 28. Communications on the main board are accomplished with parallel data and address busses, as well as serial clock and data lines. Communications for the front panel are separate from the internal main board communications. 27 DATA BUS X601 16Mhz 28 ADDRESS BUS IC601 MAIN MICROCOMPUTER 25 EVER FRONT PANEL +5Vdc COMM SERIAL CLOCK 67 RESET 86 SERIAL DATA DSPRST 90 IC605 IC604 IC611 EEP ROM SRAM DRAM Diagram 4-9. System Control. 25 On power up, the main board drives the laser mechanical 5. CIRCUIT DESCRIPTIONS assembly to check if there is a disc in the tray. If there is a 5-1. Overview disc in the tray, the main board monitors the servo feedback signals and the RF signal to determine if the disc is a DVD or Refer to diagram 5-1. Overview. a CD. The disc's table of contents is read and the player Toshiba DVD players consist of four main functional blocks; either goes into the stop mode, or, with some DVD discs, the power supply, the laser mechanical assembly, the main into the play mode. While a disc is playing, the main board board, and the front panel display. The laser mechanical constantly monitors the servo feedback signals and adjusts assembly is a collection of individual parts and PC boards. the drive signals for changing conditions. The other functional blocks are housed on individual PC boards. A color difference board is added to the SD3006 The main board processes the DVD RF signal and extracts player to output the component video signal. the MPEG2 video and whatever type of audio was recorded on the disc. MPEG2 digital video is converted to analog As long as the DVD player is plugged in, the power supply video and output as S-Video or composite video. In the is active, but only in standby mode. Only the DC supplies SD3006 player, the MPEG2 video can be converted to necessary to activate the microprocessors and the front display component video R-Y, B-Y, and Y, and output through the panel are activate. When the power button is pushed, either color difference board as Cr, Cb, and Y. The audio recorded on the front panel, or the remote, a power on signal is sent to on the disc is processed on the main board, then output as the power supply to activate the remaining DC supplies. analog left and right audio, digital PCM audio, or digital AC- 3 audio. Cr COLOR DIF Cb Y BOARD SD3006 R-Y B-Y Y SERVO FB LASER S-VIDEO DRIVE SIG COMPOSITE MECHANICAL VIDEO DVD/CD RF SIG ASSEMBLY MAIN AC-3/PCM AUDIO BOARD L AUDIO DC SUPPLY VOLTAGES R AUDIO POWER ON/OFF SUPPLY CONTROL VOLTAGES SIGNALS & DATA POWER FRONT PANEL SUPPLY DISPLAY Diagram 5-1. Overview. 26 Power is transferred to the secondary windings when the 5-2. Power Supply magnetic field around P1 collapses, and after a few cycles, the supplies are up to their full voltage. Until the power is Refer to Diagram 5-2. Power Supply. turned on, the only supplies that are active at connector The power supply in the Toshiba DVD player is a self CN801 are the Ever +5Vdc, the -24Vdc, the F+ (-16Vdc), oscillating, free running, switched mode supply with optical and the F- (-21Vdc). The Ever +5Vdc is used to power the feedback for regulation. Except for the Control IC, Q821, microcomputers, while the -24Vdc, F+, and F- are used for it s operation is typical of most free running switched mode the fluorescent display. power supplies. To prevent damage to the player or test equipment, always use an isolation transformer when The control IC, Q821, monitors the +9.3Vdc supply servicing the player. developed at pin 7 of T802 and sends an error signal from error amp 1 to the optical feedback IC, Q802. This error One hundred and twenty volts AC is applied to the bridge, signal is optically coupled to the base of the switch transistor where it is rectified and then filtered to approximately 160 to regulate the frequency of the oscillator. Since the frequency Vdc by filter capacitor, C805. The 160Vdc is applied to pin of the oscillator determines the amount of power coupled to 3 (the collector) of switch, Q803, through the primary the secondaries, the supply can regulate itself. Without the winding, P1 of transformer T802. At the same time, a small feedback, the supply cannot regulate itself, usually causing start up voltage derived from the 160Vdc is applied to pin 2 failure of the switch in the primary, as well as various other (the base) of Q803 through resistors R804 and R805. This components. Often, these types of supplies have cascade positive voltage on the base of the transistor turns it on, failures that can only be isolated while the supply is operating. allowing current flow through the primary winding P1 of Always bring the line voltage up slowly with a variac, to T802. A magnetic field starts building around all of the prevent damaging any repairs already made. windings in T802; however, no secondary voltages are developed at this time due to the polarity of the secondary During normal operation, the supply operates at a frequency windings and the rectifier diodes. The building magnetic of approximately 130Khz with power off and 55Khz with field developed by P1 induces current flow in P2 that is power on. However, these frequencies will vary, depending positive at pin 2 of T802. Also, since there is current flowing on the line voltage. This supply maintains regulation down in P2, P2 develops it s own small magnetic field with the to a line voltage of about 25 VAC with power off, and about same polarity as the field developed by P1. The positive 50 VAC with power on. voltage developed by P2 is applied to the base the Q803 to saturate it. Eventually, collector current reaches maximum and the magnetic field around P1 stabilizes. Current no longer When the player is turned on, the microcomputer on the main flows in P2, so the positive voltage applied to the base of the board applies +5Vdc to the power supply via pin 3 of CN801. transistor disappears. The small magnetic field around P2 The +5Vdc is inverted to a low by Q827 and is applied to the collapses, making pin 2 of T802 negative with respect to pin on/off block in Q821, the regulator Q824, and the switch 1, and the transistor turns off. Current flowing through P1 Q825. Inside the control IC, the on/off block turns on ceases and the magnetic field collapses. As this field collapses regulator 2, applying the analog +5Vdc supply to pin 4 of it induces current flow in P2 that is negative at pin 2 with CN801. The on/off block also turns on error amp 2, allowing respect to pin 1, and P2 builds its own small magnetic field. regulator Q822 to supply 3.3Vdc to pin 8 of CN801. Once P1's field has completely collapsed, the small magnetic Regulator Q824 is allowed to supply the +9Vdc via pin 5 of field around P2 collapses, making pin 2 positive with respect CN801, and the +8Vdc at pin 6 through D835. Switch Q825 to pin 1. This positive voltage is applied to the base of the allows the control IC to control regulator Q823, in turn transistor, turning it on. Now that the oscillator has started, supplying the digital +5Vdc at pin 7 of CN801. it can continue oscillating even if the start up voltage is removed. 27 There are three simple protection circuits that can shutdown The third shutdown circuit monitors the temperature of the the power supply. control IC, Q821. If the temperature of the control IC rises above the operating threshold of the circuit (approximately 130 degrees, celsius) all of the positive supplies are turned T he first of these consists of diodes D831, D832, and D833. off. If either the +9Vdc, +8Vdc, or digital +5Vdc supplies is shorted to ground, a low is applied to the base of Q827, turning the supply off just like an off signal from the This supply runs unloaded at full line voltage, so it s easy to microcomputer. check for loading on any of the sources. Also, a jumper can be inserted between pins 2 and 3 of CN801 to activate all of The second protection circuit is an over voltage shutdown the sources during troubleshooting. that monitors the +9.3Vdc supply derived from pin 7 of T802. If this supply exceeds 11 volts, D828 conducts and turns on Q828, which in turn shuts the supply down by applying a low to the base of Q827. EVER TEMP REG1 1 2 +5Vdc Q821 SHUT REG2 CONTROL IC 4 DOWN ERR ERR ON 130 C ANALOG REG3 AMP 1 AMP 2 OFF +/- 20 C +5Vdc 4 Q827 5 13 12 9 8 2 6 POWER ON/OFF T802 3 D831 +9.3Vdc SW TRANSFORMER D821 Q825 7 REG C821 +9Vdc Q824 6 5 FILTER Q828 C822 C805 D828 P1 D833 D822 (11V) 8 REG DIGITAL START C823 3 Q823 +5Vdc 7 +5.8Vdc UP C824 D832 R804 +8Vdc 6 R805 D835 9 +4.3Vdc REG D823 +3.3Vdc Q822 3 C825 8 Q803 2 10 SWITCH 11 4 D824 12 C826 -24Vdc -36Vdc 12 C835 2 13 3V F+ D825 P2 -16Vdc 14 C828 1 14 F- C836 -21Vdc 13 Q802 21V 2 4 CN801 OPTICAL FEEDBACK Diagram 5-2. Power Supply. 28 The DSPCK signal is the serial clock, which consist of eleven 5-3. Front Panel Display low clock pulses during one low period of the FSTBX signal. Refer to Diagram 5-3. Front Panel Display. Serial data from the main board to the front panel is transferred on the DSPSO signal, and serial data from the There are two main functions of the front panel in a Toshiba front panel to the main board is transferred on the DSPSI DVD player. The first of these functions is to display the signal. All of these signal are applied to the serial transfer status of the player, and the second is to interpret and block in the display microcomputer. communicate user commands from either the front panel buttons or the remote control to the main board. Three components, the Fluorescent Display, the Remote Sensor, User commands are sent to the serial transfer block in the and the Display Microcomputer comprise the majority of display microcomputer either by the remote control sensor, the front panel. A flex cable connects the front panel to the via pin 22, or by the buttons on the front panel via pins 9 and main board via CN101, and supplies all power and 10. The key process block in the microcomputer monitors communications. the voltage levels on the KEYIN 1 and KEYIN 2 inputs to determine when a button is pressed. For example, when the power button is pressed the voltage on the KEYIN 1 input Power for the fluorescent display is the -21Vdc (F-) input on drops from 5Vdc to +2.5Vdc, signaling the microcomputer pin 1, and the -16Vdc (F+) input on pin 2. The display to turn on the player. Similar voltage level changes occur microcomputer requires two supplies, the Ever +5Vdc via on each line for all of the buttons on the front panel. pin 9, and the -24Vdc (Vkk) via pin 3. Refer to the diagram 5-4. Grid and Cathode chart. Communication signals are the FSTBX on pin 4, the DSPCK on pin 5, the DSPSO on pin 6, and the DSPSI on pin 7. The The fluorescent display is driven by the combination of the DSPRST signal on pin 10 is a +5Vdc reset high signal, which signals on the grids, G1 through G7, and the anodes, P1 resets the display microcomputer when power is applied to through P16. An element is illuminated when both the anode the player. The FSTBX signal is an enable signal which signal and the grid signal are high. This chart is also on page allows communications between the two boards during low 3-14 of the service manual. transitions. Use the FSTBX signal as a trigger and reference all other signals to it when viewing the communication signals Timing for the microcomputer is supplied by the 8Mhz with a scope. crystal, X101. 29 MEMORY TITLE CHP/TRK TOTAL REMAIN CD A-B RANDOM CHP/TRK DVD TITLE F- (Pins 1&2) F+ (Pins 41&42) G1 - G7 (Pins 5 - 11) S1 - S16 (Pins 21 - 38) 1 -21Vdc (F-) 2 -16Vdc (F+) S1 - S16 G1 - G7 (Pins 28 - 34) (Pins 1-8, 35-38, 41-44 ) CN101 Power (+2.5Vdc) KEYIN 1 9 Open/Close (0Vdc) KEYIN 2 10 Play (0Vdc) KEY FLUORESCENT 11 Skip FW (+1.25Vdc) PROCESS DISPLAY DRIVER 12 +5Vdc Skip REV (+2.5Vdc) (KEYIN 3 & 4) Pause (+3.8Vdc) 4 23 FSTBX DISPLAY 5 26 DSPCK MEMORY 24 6 DSPSO SERIAL 25 7 DSPSI TRANSFER 10 15 ICX01 DSPRST 22 DISPLAY CN101 MT101 MICROCOMPUTER REMOTE 13 14 39 40 9 SENSOR Ever +5Vdc 3 X101 8Mhz Vkk -24Vdc CN101 Diagram 5-3. Front Panel Display. 7G 1G 2G 3G 4G 5G 6G MEMORY TITLE CHP/TRK TOTAL REMAIN CD A-B RANDOM a 2a 1a a 2a 1a 2a 1a 2a 1a 1f 1b 1g CHP/TRK 1e 1c DVD 1d col col TITLE GRID 3G 7G 1G 2G 4G 5G 6G ANODE a 1a CD 1a 1a A- P1 1a P2 1b b 1b 1b 1b B P3 1c 1c 1c c - 1c RANDOM 1d 1d 1d - d P4 1d DVD - e P5 1e 1e 1e 1e TITLE P6 1f f 1f 1f 1f MEMORY P7 1g g 1g 1g 1g CHP/TRK P8 - - - - -- - 2a - 2a 2a P9 - 2a a 2b - 2b - P10 2b 2b b P11 2c - 2c - 2c 2c c 2d - 2d - 2d P12 2d d 2e - 2e - 2e 2e e P13 - P14 2f - 2f 2f 2f f - P15 2g - 2g 2g 2g g - P16 - TITLE CHP/TRK TOTAL REMAIN Diagram 5-4. Grid and Cathode Chart. 30