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| ESR Testing and "in-circuit" -- Please explain |
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| MosherIV:
Hi. I already posted saying that from your description, it is not likely to be bad capacitors. Symptons of bad capacitors would be : does not turn on, turns on for a while then turns off by itself. A dim screen is more likely to be the backlight. I looked up your monitor model, it was not clear whether the backlight is EL, flouresnt tube or LED. I would assume it is EL or flouresent tube. As I said before, you can get replacement back light kits. You get replacement EL or flourcent tubes or a kit to replace them with LEDs. |
| crosis:
--- Quote from: MosherIV on November 02, 2018, 07:48:42 am ---Hi. I already posted saying that from your description, it is not likely to be bad capacitors. Symptons of bad capacitors would be : does not turn on, turns on for a while then turns off by itself. A dim screen is more likely to be the backlight. I looked up your monitor model, it was not clear whether the backlight is EL, flouresnt tube or LED. I would assume it is EL or flouresent tube. As I said before, you can get replacement back light kits. You get replacement EL or flourcent tubes or a kit to replace them with LEDs. --- End quote --- Thanks, Mosher. This is my first time with such a repair so was hoping the solution would be a simple cheap capacitor replacement. To be honest this is all more an exercise in simple electronic repair than a dire need to restore a monitor. Still though i've explored the capacitor route so will indeed investigate the back light approach. For the record a label on the light back panel reads: LG LM220WE1-TLP4. Search returned - Type: a-Si TFT-LCD , LCM // Light Source CCFL [2 pcs] , 50K hours Again, thank you very much, Mosher for helping me out. All this is new to me! |
| MosherIV:
Hi No problem. Hope you learned about capacitors and esr. --- Quote ---Light Source CCFL [2 pcs] , 50K hours --- End quote --- This means "cold cathode flouresent lamp" with a life of 50,000 hours. I think you have reached that limit hence the screen is getting darker because the flourecent lamps are getting dimmer. From your picture of the psu board, they are powered from cn1 and cn2. They should take around 150Volts. The only way to restore the brightness is to replace the lamps. |
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