Repairing the DELL E153Fpc LCD with the complaint of display shutdown after few seconds (power LED still on) was not difficult. Normally once this kind of drawback happens, we would first suspect the inverter board, then the filter capacitors and lastly the main board.
A defective in one of the lamps and a faulty TL1451AC PWM IC or inverter IC may cause the display to shutdown as well. If the lamp is flawed, it will send a feedback to pin 3 or 14 of TL1451AC IC and caused it to stop producing output signal thus the display just shut off once you switch it “On”.
The power board is employing a SG6841D PWM IC and a FQPF7N80 power junction transistor. You can conjointly use different half numbers to substitute the ability junction transistor just like the K1118.
As usual, after opening up the cover, bush tv repair london would first check for any burnt components, loose connector, cracked board, dry joints and etc before doing the voltage test.
Upon scanning for any unhealthy elements before beginning the voltage take a look at, I found a filter capacitor that had turned into darker colour. Using the ESR meter disclosed the ESR ohm has increase to twelve ohms. This filter electrical device situated at C922 with the worth of one thousand small F sixteen V.
If you don’t have the ESR meter you’ll be able to forever use the digital capacitance meter. The value that I got from measurement the unhealthy electrical device was fifty seven microfarad.
Now, the question is why a filter electrical device will cause the show to shutdown? If you rigorously see the image, I’ve drawn the yellow path to point out you the way the voltage is flowing. By the way, the Vage at the unhealthy filter electrical device line is twelve volt. The voltage saw a SMD electronic transistor within the begin circuit and flow straight to pin nine (VCC) of TL1451AC IC.
In order to let the 12 volt to flow through the transistor and reach the VCC pin of the IC, first, an ‘ON’ signal must be sent from the main board to trigger the transistor. If no signal send to the transistors (off signal), both transistors in the Start Circuit can’t be turned on and no voltage will follow through the IC.
Thus if the most board or any of the beginning Circuit elements spoilt, there will be power but no display because the TL1451AC would not send signal to the Royer kind L, C resonant and boost circuit (that consists of C5706 transistors, capacitor, transformer, coil, FET, diode and resistors) so no high voltage produced by the high voltage transformer and this will lead to no display.
In the above case, the LCD display shutdown was due to the ripple because of the bad filter capacitor. The ripple caused the TL1451AC IC to be unstable and eventually ending the output. Replacing only the filter capacitor solved the DELL E153Fpc LCD shutdown problem.
Conclusion, don’t always presumed that LCD is very tough or difficult to repair. From the above article, you could see that the cause of the shutdown problem was only a bad capacitor. If you fully understood how LCD works, then chances for you to successfully repair the LCD is very high but again it depends on the availability of spare parts. If you ever come across any LCD sent to you for repair for the first time, go ahead and start troubleshoot it. Who knows one day LCD repair could become one of the major source of income to you and your business.