Tricks on a circuit track blank raster with IK (AKB)
Posted in category: Free Download Softwere at: January 4, 2012 by nuGMbotenGaptek Because it is still often someone asks me a dark raster cause the circuit that uses the TDA9381, so here we review the circuit IK back problems are common in Artificial Philips TDA ic.
The basic concept of IK circuit in Y / C jungle PHILIPS
- Because the life of the CRT tube, will cause the flow of electrons from the cathode each RGB will not experiencing a similar decline, thus causing white-balance is not balanced anymore.
- Circuit IK (cathode current) or AKB (automatic cathode bias) to monitor each of these RGB cathode currents. And if it does not balance anymore, then the circuit will perform adjustment IK-white balace automatically at the Y / C jungle RGB drive, to make adjustments or compensate for the current RGB cathode balanced.
- The first time the aircraft turned on the video circuit will be “blank” while, so that the raster will appear dark and the OSD does not appear. Hence-pin RGB out if measured voltage zero.
- Each pin-RGBdrive Y / C jungle in turn will generate sampling pulses. Sampling pulses generated during the vertical blangking, therefore, can sometimes be seen on the top of the screen in the form of a white line (or maybe 3 pieces if the dynamic convergent RGB lines are less precise)
- Each sampling pulse in turn causes the cathode current RGB
- Sampling RGB cathode current will in turn fed back through the circuit IK to the Y / C jungle.
- Y / C jungle will then perform an automatic adjustment to each of the RGB drive can cause the flow of cathode RGB balance.
- If the three cathode current is balance, then the video signal is not longer “blank”. Pin-out removing the voltage and RGB raster will light up and appear OSD.
- If the white balace not allow anymore the raster will remain in-blank
Because of the above – then the plane that uses IK circuit will cause the release of images becomes longer when it was first turned on, if compared with the aircraft without circuit IK.
- In circuits that use IK, then things like this will cause the screen remains blank (black)
- The vertical part is not working
- Mikrokontrol not work, or memory problems, or line SDA / SCL problem
- One of the cathode emission is weak – this will lead to an acceptable sampling IK Y / C jungle is too weak – thus resulting in automatic adjustment is never reached.
- Circuit on the CRT socket is broken. For example there is loose solder, one transistor drive is damaged, or corrupted drive ic.
- No voltage Screen voltage 180v or less.
- Feedback path of the circuit CRT socket to Y / C jungle there are parts that are damaged or broken lines.
- Y / C jungle damaged so as not to outputkan sampling pulses (this can only be traced with the oscilloscope)
- Y / C jungle is not received from the flyback pulse (FBP)
IK trick track damage
- With an oscilloscope, check each pin, RGB out whether the issue smpling pulses.
- Increase the voltage screen. Observe the line that appears at the top of the screen. If the white line (RGB out of all), then the damage caused to the feedback circuit of the CRT socket IK to Y / C jungle. If the line is not white anymore, then it is likely one of the CRT tube cathode is weak, or one drive RGB video amplifier circuit is broken
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