REPAIRING AND NOT THROWING AWAY

REPAIRING AND NOT THROWING AWAY

Richtige Fernseher haben Röhren!

Richtige Fernseher haben Röhren!

In Brief: On this site you will find pictures and technical information about Service Modes, Circuit Diagrams, Firmware Update procedure, Disassemble procedure, Universal remote control set-up codes, Troubleshooting and more....

If you go into the profession, you will obtain or have access to a variety of tech tips databases HERE IT IS Master Electronics Repair !.

These are an excellent investment where the saying: 'time-is-money' rules. However, to learn, you need to develop a general troubleshooting approach - a logical, methodical, method of narrowing down the problem. A tech tip database might suggest: 'Replace C536' for a particular symptom. This is good advice for a specific problem on one model. However, what you really want to understand is why C536 was the cause and how to pinpoint the culprit in general even if you don't have a service manual or schematic and your tech tip database doesn't have an entry for your sick TV or VCR.

While schematics are nice, you won't always have them or be able to justify the purchase for a one-of repair. Therefore, in many cases, some reverse engineering will be necessary. The time will be well spent since even if you don't see another instance of the same model in your entire lifetime, you will have learned something in the process that can be applied to other equipment problems.
As always, when you get stuck, checking out a tech-tips database may quickly identify your problem and solution.In that case, you can greatly simplify your troubleshooting or at least confirm a diagnosis before ordering parts.

Happy repairing!
Today, the West is headed for the abyss. For the ultimate fate of our disposable society is for that society itself to be disposed of. And this will happen sooner, rather than later.

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..............The bitterness of poor quality is remembered long after the sweetness of todays funny gadgets low price has faded from memory........ . . . . . .....
Don't forget the past, the end of the world is upon us! Pretty soon it will all turn to dust!

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Monday 25 March 2019

HYUNDAI F770D _ C17F15071 _ CRT MONITOR - THEORY OF OPERATION

HYUNDAI F770D _ C17F15071 _ CRT MONITOR - THEORY OF OPERATION

POWER SUPPLY
  • The AC line voltage range is from 100V to 240V.
  • The SMPS has +80V, +55V, -12V, +7.0V, +14V, +5V
  • The conducted noise is filtered by X(CP01, CP04) and Y (CP02, CP03, CP11)capacitors and a common mode line filter (LP02).
  • The input rectifier (DP01 DP04) converts the AC line voltage into a DC voltage to power the SMPS.
  • The UC3843 (ICP01) drives the power FET(QP04) according to the PWM signals generated by the RT and CT (RP07, CP10) connected pin 4 of ICP01.
  • The ICP01 is an integrated current mode PWM.
  • It consists of an oscillator, error amplifier, current sense comparator, under voltage lock-out and an MOSFET drive stage.
  • The switching frequency is locked to horizontal scan frequency by horizontal flyback pulse.
  • When the monitor is in OFF mode with no pulsed syncs. QP05 and QP07 is turned off. The total power consumption must be less than 5W in off mode.
DPMS SELF TEST MODE
  • The power supply supports the DPMS function. Its operation is shown in the table below.
MODE
H-SYNC
V-SYNC
BRI
MCU
PIN35
MCU
PIN 9
MCU
PIN 10
QP07
14V
7.0V
NORMAL
O
O
CONTROL
H
H
ON
14V
7V
SELF TEST
X
X
5 V
H
H
ON
14V
7V
STAND-BY
X
O
0V
L
H
OFF
0V
7V
SUSPEND
O
X
0V
L
H
OFF
0V
7V
OFF
X
X
0V
L
L
OFF
0V
2.3V
SIGNAL PROCESSING
The X-TAL resonates at 12MHz.
When the H and V sync or TTL composite sync are input to MCU, MCU can measures the H and V frequency to detect the video mode.
MCU has digital to analog converter(DACS) control function like ABL, H-LIN rotation, brightness, and MCU can control , Recall, H/V-Size, H/V-Position, Pincushion/Trapezoid, Parallel/Pin Balance,
H/V Moire, Color Control, Information, Language, Soft Power by I2C BUS Line.

HORIZONTAL DEFLECTION
  • TDA9116 is an I2C auto sync deflection controller for H/V sync and drive processing.
  • All functions are controlled by I2C bus.
  • When H-Sync is applied, the internal oscillator is automatically locked.
  • The duty-cycle of H-output pulse Pin 8/26 is variable by frequency.
  • QH08 and TH01 are used to drive the H-output transistor (QH09). QH09 is turned on, it conducts current through the deflection yoke on the right hand side of the screen.
  • This current comes from the S correction capacitors (CH27, CH29, CH32, CH34), which have a charge equal to the effective supply voltage.
  • When the QH09 is opened up, the damper diode(DH12) allows current for left hand side of the screen to flow back through the deflection yoke to the S capacitors.
  • The fly back capacitor (CH23) determines the size and length of the fly back pulse.
  • The S capacitors correct outside versus center linearity in horizontal scan.
  • THERE FETs (QH11, QH12, QH13) select the value of S capacitors.
  • H-centering is controlled by a switch(SWH01). The switch selects DC offset current flow through the yoke.
  • A diode modulator is used to control the E-W correction and H-size. ICH01 generates the E-W parabola wave using vertical amp.
  • A power buffer (QH02, QH03) drives the diode modulator.
  • In order to keep the high voltage constant independent of the horizontal scan frequency, the supply voltage of FBT must increase with increasing scan frequency proportionally. A step-up mode DC-DC converter with PWM is used to realize this demand.
  • ICH01 compares high-voltage feedback with reference voltage. Its output pulse switches a FET(QH07). To adjust the high voltage, TDA9116(ICH01) has a control terminal (Pin14).
VERTICAL DEFLECTION
  • In vertical section of TDA9116/TDA9302H there is auto-sync processing.
  • The vertical output stage consists of a power OP-AMP with extra flyback grnerator.
  • TDA4866/TDA9302(ICV01) is used as vertical output stage.
X-Ray PROTECTION AND BEAM CURRENT LIMITING
  • A failure in the horizontal scan control section could cause a dangerous situation; the high voltage might rise to an unacceptable high level. When the fly back voltage rise to unacceptable level, the pin25 of ICH01 detects these states over 6.2V TDA9116/over 8.6V TDA9116.  It causes the H-drive stage and oscillator to be turned off. Then high voltage is shut down until the power switch is on.
  • The average anode current is measured at lower side of the High Voltage winding of the FBT. The anode current flows through Connectors(CON04.CNC01) connected ICC01(KA2500) and through RM07 Connected ICM01 Pin38. and ABL is controlled by ICC01.
VIDEO AMP: & OSD INTERFACE
  • KA2500(ICC01) is a Very High Freguncy video amplifier with three matched video amplifiers, OSD Contrast Control SDA, SCL,OSD Interface, OSD BLK drive controls, blanking gate and clamp gate.
  • H-blank signal is applied to Pin 19. During blanking all three outputs are thrown to the pedestal level. An inserted H-sync is used to a clamp signal.
  • The signal is applied to ICC01 Pin 18.
  • Three OSD inputs (Pin 1,2,3 of ICC01) are TTL compatible and typical bandwidth is 80MHz.
  • A fast commutate pin is provided to select either the video or the OSD inputs as a source for amplification.  OSD contrast control is made by controlling simultaneously the gain of three internal variable gain amplifiers through the I2C bus interface. MTV021 is designed for monitor application to display built-in characters or fonts on to monitor screen.
  • The display operation occurs by transferring data and control information from the MCU to RAM through a serial data interface.
  • The output stage is made of 3-channel power amplifier (ICC03, LM2437). The output is capable of 40 Volts swing in less than 11 Sec.
  • The three cathodes are AC coupled to the video amplifiers. The DC level on each cathode is set by a cut-off amplifier and clamp diode. The value of the DC voltage is adjusted by DACS.
POWER MANAGEMENT SYSTEM
  • The automatic power management function saves electricity and reduces heat. Used in conjunction with a PC having Power Management function, or a PC running Screen Blanking software, this monitor automatically reduces its power consumption when the PC is not in use.
  • This monitor runs in four states:ON(Normal Operating), Stand-by(No Video Signal), Suspend(Minimum Power for Quick Recovery) and OFF(Non-Operating).
Posted By: FRANK at 02:47
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