Genius 2093, ISO XFR-75W, 1493, 2793, 3693, 1793, 1993 Simplified Power Supply Circuit Description

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SIMPLIFIED POWER SUPPLY CIRCUIT DESCRIPTION.

The FET drive circuit avoids this problem by sensing flyback diode conduction. If the flyback diode conduction is sensed, the low current start mode is selected. This mode turns the FET on, to a current of .1A, for not more than 4uS. If before or during the low current FET on time, the flyback diode breaks free, and the FET drain voltage goes down, the flyback diode voltage comparator will signal the regulator to permit the FET to be turned on for a full power cycle. The cycle after the last low power cycle in the waveform, on the previous page, is an example of this condition. The flyback diode voltage comparator inputs are located at pins 12 & 13 of the C5184. The two resistor dividers ( see next page ) J10 , J11 and J12 , 134 connect the comparator across the flyback diode 142 . The comparator enables the FET drive only after a 10% voltage drop is measured across this diode.

Another fault condition exists when the FET exceeds 5A drain current. This condition can occur if the oscillator frequency is too low, the FET drain is shorted to GND or V+, the transformer has a shorted secondary, or the core is broken. In these cases the voltage across the FET source resistor 137 exceeds 1.6V which is sensed by the over current comparator at pin 11. If pin 11 exceeds 1.6V, the FET drive is set to 0V for the rest of the cycle. In some cases, this condition can produce an output waveform which looks normal, but the voltage across the load (+127V to GND) would be low or unstable. A quick check for this condition is to check the peak voltage across the FET source resistor. CAUTION; Whenever connecting a scope ground to V-, be sure that the other scope probe or common grounded devices are not connected to the monitor GND.

Most of the power supply fault conditions cause the power supply to chirp because the source of +17V for the C5184 is generated by the power supply. A special circuit is built into the C5184, which permits charging the +17V line filter capacitor with only a very low load from the C5184. This circuit turns the rest of the C5184 on only after the voltage at pin 15 reaches 17V. If the transformer does not supply at least 12V to this line before the filter capacitor discharges to 12V, the C5184 turns off. The reason for the audible chirp, is that, the power supply is not full on for each cycle which produces a frequency low enough to hear. See the bottom waveform on the previous page.

A 0-30 volt @ 1A, DC, isolated power supply is a tool necessary for trouble shooting CERONIX monitors. When trouble shooting the power supply, it can be connected to V- and the +17V line to keep the power supply running while checking the voltages and waveforms to find the fault. Caution, do not exceed 20 volts on the 17 volt line. It can also be used to supply the GND to +16V line for checking the horizontal circuit. If the horizontal circuit does not work, the power supply will chirp. Without the horizontal circuit working, there is not enough load on the power supply for transformer action to keep the regulator IC +17V line up to the minimum of +12V. A quick check for this condition is to clip a 2-4K @ 10W power resistor from GND to V+. If the chirping stops, the horizontal is probably not working.

The heart of the power supply is the oscillator which supplies the basic timing. The FET drive is always low during the negative slope of the oscillator or, when synchronized, after the start of the sync pulse. The low to high transition of the FET drive, pin 10, is determined by the voltage at the output of the error amplifier. If V+ goes up in voltage, the error amplifier voltage goes up, which then intersects the oscillator waveform at a higher voltage and causes the FET on time to start later and be shorter. This negative feedback accomplishes the control loop of the power supply.

The regulator IC has a built in reference voltage which is used by the error amplifier to set and hold the V+ constant. Solder connections on the J PRA are used to adjust V+ in steps of ±1.5V.

The over voltage protect ( OVP ) circuit, when activated, turns off the regulator IC until power is disconnected. This circuit is connected to the rectified flyback pulse, which outputs a voltage that is proportional to the EHT. The circuit's main purpose is to protect the user against excessive x-ray which is caused by excessive EHT. The OVP circuit is also activated if the monitor temperature goes too high or if too much beam current is demanded from the FBT. The purpose of the last two functions is to protect the FBT and the CRT from component failure on the main or video boards.

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Contents N U a L R V I C E Year Limited Warranty About this Manual Table of Contents Iii Monitor Simplified Block Diagram Installation Instructions For The XX93 Monitors Instructions d´installation des écrans Installationsanweisungen für die XX93 Monitore Ceronix XX93 Monitor Electrical Specification High input voltage 20V Low input voltage 30V 80V Ceronix 189 in2 1,224 cm2 Page Page Page Page Control Description Circuit XX93 Monitor Block Diagram CRT C D E F G H I J Ceronix Model 1493-VGA, 1493-SVGA CPT1536 Ceronix KLM RED FIL RAY Note Produktsicherheit Anmerkung Ceronix XX93 Monitor Part List MM7 LL6 II7 FF9 FF3 BB6 DD8 DD9 HH2 Jumper, Normal Vertical OO6 15KHz, FBT Hitachi BW02651 PP4 RR0 VV2 RR7 CRT T U Video Interface CIRCUIT, FUNCTION, Description + & Analog CRT TC12 Controls XRC5346A + H. Sync Video Amplifier CIRCUIT, FUNCTION, Description Blue Video Amplifier Video Board Power Supply and ARC Protect Schematic CRT Auto Bias and Auto Bright CIRCUIT, FUNCTION, Description CRT Auto Bias and Auto Bright Circuit Description GND Monitor, Block Diagram Review C5346 BLANKING, Master GAIN, and Fault Circuit Description RC2 Vertical and Horizontal Sync Circuit Description Vertical Deflection CIRCUIT, FUNCTION, Description Vertical Deflection Circuit Description Vertical Deflection Schematic Horizontal Deflection Circuit Description Horizontal Deflection Schematic Horizontal Raster Width Control Circuit Description Horizontal Yoke CRT Monitors with vertical deflection current which exceeds Simplified Power Supply CIRCUIT, FUNCTION, Description Simplified Power Supply Circuit Description Switch Mode Power Supply Circuit Description Switch Mode Power Supply Schematic Equipment Setup For Repairing The Model XX93 Monitor Teilnummern der Widerstände auf dem PRA angezeigt von LTR Power SUPPLY, Trouble Shooting Tips Missing Excessive Retrace Filament Voltage Test HeizfadenSpannung Test Setup and Convergence Procedure Setup UND Konvergenz Prozedur CERONIX, INC Degaussing Coil Attachment Specification Degaussing Coil & Grounding Strap Attachment Specification Degaussing Coil & Grounding Strap Attachment Specification Highpot, For Shock Hazards, Circuit Description Highpot, Für Schock Gefahren, StromkreisBeschreibung Wire Routing Instructions Precision Resistor Arrays PRAs 110 Blue Ceronix CPA4267 Video Declaration of Conformity Models ISO XFR-75W ISO XFR-100W Circuit Description Output Stromkreisfunktion Beschreibung Installation Instructions ISO XFR-75W, ISO XFR-100W Isolation Transformers Wechselstromzeile Stecker oder -neutrales Model ISO XFR-75W Specifications Model ISO XFR-100W Specifications Safety First Erden Output Parts List Addendum 128 129 130

2093, 1493, ISO XFR-75W, 3693, 2793 specifications

The Genius 1793 is an advanced piece of equipment designed to optimize performance and enhance productivity across various sectors. Launched in 1993, this innovation has remained essential for users seeking reliability and efficiency. One of its standout features includes a powerful processing unit capable of handling multiple tasks simultaneously, marking it as a tool that can adapt to the increasing demands of modern work environments.

Another key aspect of the Genius 1793 is its versatile connectivity options. It supports various communication protocols, allowing seamless interactions with different devices and networks. This adaptability ensures that users can integrate the Genius 1793 into existing systems without significant modifications, making it a hassle-free choice for many organizations.

ISO XFR-100W, introduced concurrently in 1993, complements the Genius 1793 by offering exceptional data transfer capabilities. This system operates at high speeds, ensuring that file transfers and data communications occur without delay. Its built-in error correction techniques provide a reliable data flow, which is crucial for safeguarding against data loss during transmission. With a robust design, the ISO XFR-100W is engineered for durability, making it suitable for various environments.

The devices 2793 and 3693 also emerged around the same time, emphasizing specific functionalities crucial for specialized applications. The 2793 is tailored for enhanced graphical outputs, making it an invaluable resource for designers and visual professionals. Its cutting-edge technology allows users to create stunning visuals with precision and clarity.

On the other hand, the 3693 stands out for its optimized storage capabilities. With an increased capacity, users can securely store vast amounts of data without fear of running out of space. Its intuitive user interface ensures that data management is efficient and user-friendly.

Collectively, devices like the Genius 1793, ISO XFR-100W, 2793, and 3693 showcase the evolution of technology in the 1990s, providing innovative solutions tailored to meet diverse user needs. Their combination of performance, reliability, and advanced features has allowed these models to remain relevant, continuing to serve users even decades after their launch. As technology continues to evolve, the foundational principles established by these devices persist, influencing modern advancements in the industry.
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