This document is a service manual for Zenith Presentation Series televisions, specifically models H27E46DT, H27E46DT8, H32E46DT, and H36E46DT. These televisions utilize the CS chassis and are identified by manual part number 923-03509, model line E, and were produced in 2002.

Function Description

The Zenith Presentation Series televisions are designed for educational and business applications, offering multiple screen sizes (27, 32, and 36 inches). The CS chassis is a multi-source, multi-format display system that integrates luminance signal processing, chroma signal processing, and sync signal processing. It supports various types of direction compensation for point scan and multi scan TVs. The IC1400 handles audio functions such as stereo modulation, SAP (Separate Audio Program), and dBx noise reduction. The IC2900 is an A/V switch that determines which auxiliary video and audio signals will be processed by the video processor. The IC6000 is the main microprocessor, and IC6001 is the main memory.

The television supports a wide array of input and output connections, including:

Computer Video Input (HD15): Standard DB15 receptacle for SVGA input video signal from either PC or Macintosh format, providing a "Flicker-Free" view of the computer.
Antenna/Cable Jack: 75-ohm antenna-type signal connection for TV, cable TV line, or other video equipment.
S-Video In and Out: For input and output connections to SUPER-VHS video equipment, utilizing the S-Video signal.
Video In and Audio In: For baseband video and audio input signals from a VCR or other signal source.
Computer Audio In: Left and right audio input that can be paired with the computer data input.
Audio Out: Preamp audio output for an external amplifier.
MPI (Multiple Protocol Interface) Jack: Standard RJ11 jack for in-room entertainment and video services, and remote control programming.
Power Indicator: Scan Card power indicator LED.
Superport: An accessory module without removing the cabinet back, housed inside the TV cabinet, and removes operating power and accessory interface signals through internal connections.
EBC (Edge Board Card): Allows easy access for removing/installing accessory modules.

The ICX2201 is a chroma decoder that receives luminance and chroma signals and decodes them to YUV video with synchronization. The ICX2200 is an RGB video processor that supports multi-scan capabilities. The ICX2600 is a deflection processor and compensation circuit for multi-scan signals.

Important Technical Specifications

Video Formats:

640 x 480: 60 Hz
640 x 480: 72 Hz
800 x 600: 60 Hz
800 x 600: 70 Hz
1024 x 767: 60 Hz
DOS TEXT: 70 Hz
840 x 480: 67 Hz
832 x 768: 67 Hz

Chassis Model Information:

Model	SCR	Cabinet	Jacks	Extra Features	Resolution	Remote	Micro	Op Guide
H27E46DT	27	Table Top	11	VGA card and MPI card	800x600	124-00233-04	P221-1391-P07	206-03755
H27E46DT8	27	Table Top	11	VGA card and MPI card	800x600	124-00233-04	P221-1391-P07	206-03755
H32E46DT	32	Table Top	11	VGA card and MPI card	800x600	124-00233-04	P221-1391-P07	206-03755
H36E46DT	36	Table Top	11	VGA card and MPI card	800x600	124-00233-04	P221-1391-P07	206-03755

Power Supply: The chassis uses a cold chassis and a single sided circuit board that has been developed for screen sizes 27" through 36". Two power supply features (two switch mode power regulators) provide voltages. One is intended for Standby sources and the other one supplies the main switched voltages. Both power supplies use direct regulation. One error amplifier and one optocoupler are used for each power supply. This chassis is Energy Star compliant for low power consumption in standby mode (less than 3 watts of consumption).

Switch Mode Regulator: This chassis has a switching power supply (quasi-resonant topology type). The AC line is routed through the filter TX3400 (5A @ 250V), fast blow, and then through the bridge rectifier circuit BR3400 and CX3407. The AC operation range is between 90 Vrms to 135 Vrms. A filter consisting of CX3400 and CX3401 is employed to reduce noise from the AC line and vice versa (EMI). The voltage output of the rectifier (150VDC) is supplied to the Main Switch Mode Regulator Power Supply (SMPS) & Standby Switch Mode Regulation Power Supply. Its output should be operating in the range of 127.3 VDC to 190.9 VDC.

Horizontal Deflection and HV Generation: The Horizontal Deflection circuitry is a common flyback type used in many television and monitor applications. QX3200 is the horizontal output transistor. When QX3200 is initially turned on, current is allowed to flow from the B+ supply, through TX2900, T3201, and QX3200. This allows energy to be stored in T3201. When QX3200 is turned off, some of this energy is returned to charge the S-capacitor(s) CX3203, CX3204, and CX3205. After several cycles (repeating at scanning frequency), sufficient voltage appears across the S-capacitor (including an additional path producing current flow though the horizontal deflection yoke coil (connector 4X2). The Damper Diode DX3200 provides the negative current path. The result is positive and negative sawtooth current through the horizontal deflection coils (approximately 11 to 17 Amps, peak to peak).

Usage Features

Remote Control (MBR3447C 124-00233-04):

POWER: Turns TV On or Off.
FLASHBK (Flashback): Returns to previous Channel.
MODE: Selects the remote's mode of operation.
SURF: Turns Surf Channel On/Off.
MUTE: Turns sound Off and On while picture remains.
CHANNEL (Up/Down): Selects next channel in TV's memory. Press and hold to repeat.
VOLUME (Left/Right): Increases TV's sound level.
NUMBER PAD: Selects channels directly.
ENTER: Stores Channel/Time, enters channel, or removes any on screen menus.
MENU: Displays menus for TV and other options.
QUIT (Three Functions Key): Exits from on-screen display, turns the remote control programming on or off, and switches audio between Main source and PIP source.
LEFT/RIGHT ARROWS: Chooses and shows the desired menu option.
UP AND DOWN ARROWS: Moves highlighted bar within menu to select an option.
A, B, C Keys: Special features of some TV's.
CC: Displays closed caption menu.
TIMER: Displays the Sleep Timer menu. Press repeatedly to set desired TV shut-off time.
TV/VCR SOURCE: Steps through source options.

Programming the Remote: The remote is already programmed for most common codes (101 VCR + 201 CABLE + 353, and AUX + 401). If your remote fails to control your Zenith products, you'll have to program the remote.

Auto Find: If the codes in the table locate your equipment, use Auto Find to search for the proper code.

Volume Override: The remote can override TV, VCR, or Video Disk Player volume functions with an amplifier's volume and muting.

Auxiliary Capability: The remote can control up to seven devices. If the remote has been programmed for four components using the TV, VCR, CABLE, and AUX keys, you may also program it for up to three additional using AUX+1, AUX+2, and AUX+3.

QuickSet II Programmer LT2000: This tool allows custom setup and programming information to be easily copied from a master TV into multiple television sets. The LT2000 can clone programmable labels, but the LT1500 cannot. Once learned from the master, setup data is retained in the LT2000 for future use and recalls.

User Menus: The television offers a comprehensive menu system for adjusting various settings, including:

Setup Menu: Auto Program, Add/Del/Blnk, Ch. Label, Clock Set, Captions, Alarm, Language.
Audio Menu: Bass, Treble, Balance, Audio Mode, SoundRite, Front Surround, Speakers, Audio Pref.
Video Menu: Contrast, Brightness, Color, Tint, Sharpness, Picture Pref.
Parental Control: MPAA Rating, Age Block, Content Block, Set Hours, Set Password, Lock On/Off.
Source Menu: Antenna/Cable, Camport, Aux Video, S-Video, Front Computer SVGA, Rear Computer SVGA, Rear Computer NTSC Out.
Caption Setup: Select CC Type, CC Caption, CC Mode, Caption Lock.

Maintenance Features

Product Safety Servicing Guidelines:

Important Safety Notice: Only properly trained audio-visual service technicians should perform repairs.
X-Radiation: Follow specific procedures to minimize X-radiation exposure, especially when replacing components.
Implosion: Direct view picture tubes are equipped with an integral implosion protection system. Always use recommended replacement tubes.
Fire and Shock Hazard: Be sure that all components are positioned to avoid a possibility of shorting. Use exact replacement components.
Servicing Information: For continued protection from AC line shock, after the original service problem has been corrected, make a check of the antenna system.
Shutdown Circuit Operation: The flyback pulse voltage from Pin 6 of T3201 (Flyback Transformer) is detected (rectified) by the action of diode DX206 and capacitor C3214. This voltage is applied to Q3214 representative of the CRT anode voltage (HV) produced by T3201. This voltage is divided down by precision resistors RX3214, RX3215, RX3216, and RX3217. This voltage appears on the positive input (pin3) of IC3201. In the event the CRT anode voltage becomes excessive, IC3201 will be higher than inverted input of pin 5. This voltage is sent to the base of Q4000 causing horizontal drive to be disabled and latched, which removes the HV. In about 5 seconds, the shutdown circuit resets.
Purity & Convergence Setup Procedure: This involves adjusting purity tabs, convergence rings, and wedges to ensure proper color display and geometry.
Improving CRT Corner Purity: CRTs that display corner purity problems even after following the service procedures can be modified with a picture-correction kit.

Component Parts List: The manual provides a detailed list of components, including their reference number, part number, and description, for various models (H27E46DT, H27E46DT8, H32E46DT, H36E46DT). This list is crucial for identifying and ordering correct replacement parts during maintenance and repair.

Critical Safety Components: Critical safety components are identified by the letter "X" in their component designators and are shaded. Replace only with part numbers specified in the manual to ensure continued safety and performance.

Zenith Presentation Series - Page 94

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