I have a BenQ FP747 monitor that when you turn it on, the power light flashes on and off, but nothing on the monitor screen. I connected my husband's work monitor to the BenQ's cables and it works fine. A friend of mine checked the monitor out and said that there's voltage going in, but none going out to power up the unit. BenQ was willing to fix it for 100-200, but won't sell the part(s) directly to an individual. What part(s) do I need and where can I order them????
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Re: monitor won't power on
PF747 has internal switch-mode power supply. Old LCD monitors have external low voltage (12VDC) power supply which can easily be replaced by any brand provided the voltage and current is the same.
On your monitor, th epower supply module is built inside the unit. When you say that the LED is flashing, this means two things,
1. The power supply is attempting to start, but the load (or current) is above its limit and it automatically switch off, then tries to start again and so on. This can be a problem with the load (minitor intelligence or the mainboard, hv supply for the flourecent back supply)
2. It can be that the power supply module is defective
In any any case, the only way to find out is to disconnect the load from the internal power supply (the monitor have to be opened), and measure the voltage at the terminal. In many devices the output will be 12 volts and in some cases there will be also 5volds supply.
If there are correct voltage present, then the supply is OK and most probably the mainboard or the HV supply is defective. If there are no voltage present, then the power supply module is defective. You can either fix this module, replace with exact new module or if you have a spare external powersupply, you can use this to provide the power to the internal circuit.
The last option is recommended only if you have experience in electronics repair.
If you cannot do the repair yourself and will cost USD200, buy a new monitor.
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1. Verify the monitor's power cord is plugged firmly into the wall outlet and the back of the monitor.
2. Verify the monitor cable is firmly connected to the computer and the monitor.
3. Verify that you have turned the monitor power switch on.
4. If the power light on the monitor is not on, test the wall outlet (plug in a light or something you know works).
5. If the power light on the monitor is not on, try a different power cord.
6. If the power light is on and yellow or flashing, but nothing displays, or the display is incorrect, borrow a monitor from a friend. If that works, your monitor probably needs replaced.
7. Also, you could try your display on a friend's computer. If it doesn't work, your monitor probably needs replaced. If it works properly on your friends computer, the problem may be with your computers video output port, motherboard video chip (or video card, if you have one), or drivers.
Try connecting the monitor to a different computer, e.g., a laptop.
The power-cord to the monitor seems to be OK.
Check the "data" cable between the monitor and the computer -- try a different cable.
With the monitor turned on, restart your computer, and watch the monitor. The computer should show some start-up messages (white text over black background), followed by the Windows "splash" screen. If it does, the monitor is working correctly.
Check the cable on your monitor through video card if there is loose connection. Check also the video card by replacing it with your extra video card if you have. I think the problem is not the monitor but the video card.