Dell E152Fpb How To Repair LCD Monitor
The criticism for this DELL E152Fpb LCD Monitor was when switched on has energy (LED lit) but no display. LCD Monitor is different from the CRT Monitor where you could feel the static on the front of the picture tube or hear the speeding sound from the high voltage produced by the flyback transformer. In LCD, if no display you will not be capable of know if the inverter board is working or not except you use an oscilloscope to point near the inverter board and the scope might display a waveform indicating the inverter board is functioning.
A faulty essential board could cause no display downside in LCD Monitor. If there is a problem in the principle board, it could not ship a "on" (enable) sign to the soft start circuit and no voltage will movement to the inverter IC thus no waveform produce by the high voltage transformer.
In the above case, after the quilt was removed, the very first thing I check was the vcc (provide voltage) to the inverter IC. This model is using the well-known TL1451ACN Pulse width modulation (PWM) IC-some most popular to name it as inverter IC. Pin 9 is the VCC provide input and it ought to have about 12 Volts when the facility is "on". Measuring the pin with my devoted digital multimeter, it reads only about three volts which indicates there's a problem in the provide line. It might be components which might be faulty that dragged down the road or it might be the swap mode energy provide itself that do not produce enough power.
As a way to find the reply as which section is giving drawback, the first clue was that the ability LED indicator lit and this show that the IC is supplying sufficient power to the circuit. Another clue was that the meter is registering about sixteen volts at the enter of the 2A fuse. Because of these clear answers, we can conclude that the change mode power supply is working fine. You can also use a 12 volt light bulb to confirm it. You could read my other publish on LCD Monitor repair articles which talks about utilizing 12 volt mild bulb for troubleshooting purposes.
I kept on asking myself, why the voltage drop to three volts after the fuse. Earlier than the fuse it reads about sixteen volt but after the fuse it reads only three volts! I did not suspect the fuse, as a result of the fuse can solely either sure or no and no in between. The first circuit that I checked was the beginning circuit but all parts checked to be okay. I even desoldered the pin 9 of TL1451ACN inverter IC just to verify it isn't this IC that pulled down the voltage.
This drawback actually challenges my troubleshooting and repairing ability, because virtually all suspected components already checked to be working. Even the beginning circuit transistors (C945 & A733) I direct changed, afraid they would breakdown when under load. The only element that I did not test was the fuse! Through the use of my meter placed across the fuse, as a substitute of getting low ohms or zero ohm studying I received 1.012 Kilo ohms! I've acquired a surprised and don't imagine that a fuse can actually go into high ohms instead of open circuit. I at all times thought that a fuse is either shut or open circuit. A fuse with zero ohms become excessive ohm thus the 16 volts dropped to three volts! I've came throughout lots of this sort of fuse however that is the primary time a fuse became high resistance.
Replacing the fuse only put the DELL E152Fpb LCD Monitor again to life. The lesson discovered from here is that do not assume that a part is all the time in a superb working condition. You have to confirm it with your meter and in the event you still suspect the component is giving drawback, merely exchange it with a identified good one and retest the equipment. Semiconductors can breakdown when below full working voltage.
Dell E152Fpb How To Repair LCD Monitor
The criticism for this DELL E152Fpb LCD Monitor was when switched on has energy (LED lit) but no display. LCD Monitor is different from the CRT Monitor where you could feel the static on the front of the picture tube or hear the speeding sound from the high voltage produced by the flyback transformer. In LCD, if no display you will not be capable of know if the inverter board is working or not except you use an oscilloscope to point near the inverter board and the scope might display a waveform indicating the inverter board is functioning.
A faulty essential board could cause no display downside in LCD Monitor. If there is a problem in the principle board, it could not ship a "on" (enable) sign to the soft start circuit and no voltage will movement to the inverter IC thus no waveform produce by the high voltage transformer.
In the above case, after the quilt was removed, the very first thing I check was the vcc (provide voltage) to the inverter IC. This model is using the well-known TL1451ACN Pulse width modulation (PWM) IC-some most popular to name it as inverter IC. Pin 9 is the VCC provide input and it ought to have about 12 Volts when the facility is "on". Measuring the pin with my devoted digital multimeter, it reads only about three volts which indicates there's a problem in the provide line. It might be components which might be faulty that dragged down the road or it might be the swap mode energy provide itself that do not produce enough power.
As a way to find the reply as which section is giving drawback, the first clue was that the ability LED indicator lit and this show that the IC is supplying sufficient power to the circuit. Another clue was that the meter is registering about sixteen volts at the enter of the 2A fuse. Because of these clear answers, we can conclude that the change mode power supply is working fine. You can also use a 12 volt light bulb to confirm it. You could read my other publish on LCD Monitor repair articles which talks about utilizing 12 volt mild bulb for troubleshooting purposes.
I kept on asking myself, why the voltage drop to three volts after the fuse. Earlier than the fuse it reads about sixteen volt but after the fuse it reads only three volts! I did not suspect the fuse, as a result of the fuse can solely either sure or no and no in between. The first circuit that I checked was the beginning circuit but all parts checked to be okay. I even desoldered the pin 9 of TL1451ACN inverter IC just to verify it isn't this IC that pulled down the voltage.
This drawback actually challenges my troubleshooting and repairing ability, because virtually all suspected components already checked to be working. Even the beginning circuit transistors (C945 & A733) I direct changed, afraid they would breakdown when under load. The only element that I did not test was the fuse! Through the use of my meter placed across the fuse, as a substitute of getting low ohms or zero ohm studying I received 1.012 Kilo ohms! I've acquired a surprised and don't imagine that a fuse can actually go into high ohms instead of open circuit. I at all times thought that a fuse is either shut or open circuit. A fuse with zero ohms become excessive ohm thus the 16 volts dropped to three volts! I've came throughout lots of this sort of fuse however that is the primary time a fuse became high resistance.
Replacing the fuse only put the DELL E152Fpb LCD Monitor again to life. The lesson discovered from here is that do not assume that a part is all the time in a superb working condition. You have to confirm it with your meter and in the event you still suspect the component is giving drawback, merely exchange it with a identified good one and retest the equipment. Semiconductors can breakdown when below full working voltage.
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