Backlight turns off after 2 seconds
I have an HP 2509b monitor that is experiencing backlight failure. After turning the monitor on, the backlight turns on and then off shortly thereafter. I have replaced the CFLs (thinking they may be bad) and checked a power supply mosfet and diode one YouTuber recommended replacing. I have also visually checked the capacitors; they all look fine. Yet still, the problem remains. What could be causing this issue, and how may I go about fixing it from here?
Thank you!
Edit:
Added photos of the power supply. The red wire was a fix of mine when a PCB trace came off with the MOSFET. (I removed it to test the MOSFET earlier in the repair).
Is this a good question?
3 Comments
Hi,
When the backlight goes out how do you get it to come on again?
Is the monitor connected to a PC?
If so have you checked the power management features settings in the PC?
Does the green power light on the monitor also go out?
If not does it change to amber?
If you press the menu button does the menu stay visible on the screen?
When the backlight turns off and if the monitor is still powered on with a green light and you had a picture before it turned off can you still see the picture on the screen by shining a torch at an angle close to the screen to see if the picture is still detectable?
Sorry about all the questions just trying to narrow it down a bit.
by jayeff
@jayeff,
Thank you for getting back with me. The backlight resets after power off. It is not currently connected to a PC, although I did try connecting it to my computer (with the same result: so signal for two seconds and then no backlight). I can't seem to change the input source without the backlight as it is too dark to see the input settings even with a flashlight. The power light is blue but occasionally turns amber. Also, I am unable to access the menu (at least the No Signal remains when I push the menu button).
Thank you again for your assistance!
by Jay Developer
Can you post a picture of the capacitors on the power supply board? Your symptoms are very indicative of capacitor failure.
by Minho