Hey guys, I have a rather strange problem concerning a laptop screen
Brief history:
A friend gave me a laptop to repair, saying that the screen will only turn on for a few seconds.
I have verified this by using the fn and a key used to change between the LCD and an external monitor. every time I change from external monitor to LCD, the screen lights for just over a second.
I have connected and external monitor to the laptop which works perfectly and when the LCD is use, the screen is FAINTLY visible.
After googling this problem i found numerous people with this problem, the general concensus was that the inverter(which transforms a dc voltage in to a high frequency, high voltage signal which powers the screen) was damaged. Before getting a replacement i checked the voltages from the motherboard and they corresponded to the voltages on the other end of the cable which rules out the cable between the motherboard and the lcd from being a problem.
I have since replaced the inverter and the problem hasnt changed!!
The cable I have been referring to a 6 pin cable.
The voltages I have measured on these pins are as follows:
pin 1: 0V (for lcd and external monitor)
pin 2: 0V(for lcd and external monitor)
pin 3: nearly 3V, around 2.7 If i recall (when on lcd otherwise 0 when on external)
pin 4: 5 volts (when on lcd, 0 when on external)
pin 5: 19.6 (when on lcd and external)
pin 6: 19.6 (when on lcd and external)
I dont think the problem is with the LCD panel itself as I have used a multimeter to carefully tell when the inverter is powered, and when the screen is not lit, the inverter is not outputting high voltage
(before any of you mention it, i merely moved the probe of the multimeter near the inverter, i did not make electrical contact with it)
I do not what the correct voltages of these pins are supposed to be, so could anyone tell me are these correct?
If they are not then I am really stumped as to what the problem could be...
its extremely unlikely but i could have just replaced the inverter with a faulty one!
Help!
Brief history:
A friend gave me a laptop to repair, saying that the screen will only turn on for a few seconds.
I have verified this by using the fn and a key used to change between the LCD and an external monitor. every time I change from external monitor to LCD, the screen lights for just over a second.
I have connected and external monitor to the laptop which works perfectly and when the LCD is use, the screen is FAINTLY visible.
After googling this problem i found numerous people with this problem, the general concensus was that the inverter(which transforms a dc voltage in to a high frequency, high voltage signal which powers the screen) was damaged. Before getting a replacement i checked the voltages from the motherboard and they corresponded to the voltages on the other end of the cable which rules out the cable between the motherboard and the lcd from being a problem.
I have since replaced the inverter and the problem hasnt changed!!
The cable I have been referring to a 6 pin cable.
The voltages I have measured on these pins are as follows:
pin 1: 0V (for lcd and external monitor)
pin 2: 0V(for lcd and external monitor)
pin 3: nearly 3V, around 2.7 If i recall (when on lcd otherwise 0 when on external)
pin 4: 5 volts (when on lcd, 0 when on external)
pin 5: 19.6 (when on lcd and external)
pin 6: 19.6 (when on lcd and external)
I dont think the problem is with the LCD panel itself as I have used a multimeter to carefully tell when the inverter is powered, and when the screen is not lit, the inverter is not outputting high voltage
(before any of you mention it, i merely moved the probe of the multimeter near the inverter, i did not make electrical contact with it)
I do not what the correct voltages of these pins are supposed to be, so could anyone tell me are these correct?
If they are not then I am really stumped as to what the problem could be...
its extremely unlikely but i could have just replaced the inverter with a faulty one!
Help!