After 1 hour the backlights fail. turn it off and on and they fail in another hour, the mother board tells the power supply to turn on the backlight. something is wrong with the mother board. do you have any circuit diagrams. i'm in australia
While I do not have the schematic handy I dare say that if you are correct that the logic board is turning off the backlights and not something else then your solution to the problem is just bypassing that signal and keeping them on.
it's a hack, I know, but that's what I'd do first after determining that main is shutting them off.
On another note I'd try to see what happens if I decrease light level to minimum - will it affect the time when it turns off?
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SOURCE: lg l1710 inverter board fault
May i know the model and the make of the product in details so that it can help me resolving the issue is a more prompt manner
SOURCE: "Upgrade" of Backlight Panel
just replace what failed.
I replace the surface mount FETs on the inverters.
SOURCE: HDTV backlight turn off after 10-15 minutes, with some t-shooting
I have read everything I can find on the net about this problem for Polaroid TLX 04240b TVs (most, like mine, bought from Wal-Mart on Black Friday after Thanksgiving). I thought I was on a hot lead when I changed a 220uF 450v capacitor, but I still had the same problem. I saw a short post from somewhere else on this Fixya web site (sometimes I can find it again and sometimes I have trouble locating it) that said someone flipped a tiny switch on their circuit board and the problem was gone. I did the same thing and my set has been working fine. They had said their set was on for over 8 hours two days in a row when they posted. The other night my daughter left our set on over night for 20 hours and the picture still was working great. If you look through the top of the set when the picture is on you can see some white light at several locations, when the screen goes blank the white lights go out and a red LED light can be seen. If you take off the plastic cover on the back (3 screws) and then take off the metal cover (3 screws) this red LED light is on the upper circuit board in the lower left corner. Just a little to the right of the LED light is a small switch block that has 4 tiny white switches. I turned my set off and took the bottom switch (#4 and had the letters BURN by it) to the right "ON" position, turned the set back on and, so far so good. PLEASE NOTE!!! I know almost nothing about how transistor circuits work. I have no idea what the switches do or what long term effect this might have on the set. The set was only good as a paper weight before so even if this only fixes the set for a short time it was at least worth a try for me. Does anyone know what those switches are supposed to be for????
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SOURCE: Power-on LED AL1916 acer LCD screen doesn't work, no display
Hi - I've just fixed ny AL1921 which would be similar to yours internally. There are a couple of issues which are common:
Bad soldering around some of the copper coils (insulation may not have been properly stripped and leads to intermittent connection and (much more likely)
Blown electrolytics.
If you have ANY electrolytics on the main board which are swollen at the top or have electrolyte oozing out of them at the top or where they meet the board, then replace them.
My ACER started flickering and switching off randomly (no power light on the front either) and I though the power supply inside was toast. However, I found two electrolytics on the large power board (1000u / 16v) which had a black crust at the top. I replaced these and the monitor sprang back into life. Try to use replacements which have a temperature rating of 105 degrees C. Basically I think these things give out just after the guarantee runs out.
Hope that works for you.
SOURCE: Philips LCD 170S Backlight problem.. only turns on
It can be DC filters caps with leaking/bulging tops, or they have high ESR, bad transistors or IC or transformers in the backlight inverter circuits, bad lamps assemblies. Please read below and look at the pictures of bad caps, failed monitors, and troubleshooting guides. Basic LCD monitor troubleshooting guide: http://en.wikipedia.org/wiki/Capacitor_plague Capacitors kit: http://lcdalternatives.auctivacommerce.com/ he can make you a set of caps for you.
If you are going to DIY and have proper tools and know safety precaution then please read on:
Most common failures in the LCD monitors are bad capacitors (bulging top/seal or leaking) in the power supply (they should be replaced in a set), blown fuses; poor solder joints, failed inverter circuits (blown fuse, shorted transistors, shorted/open transformers), bad lamps (poor solder connections or worn out lamps). You will need to open it up and inspect the inside, see example of failed monitors to get some ideas what to look for: http://s807.photobucket.com/home/budm/allalbums
Post back what you see inside so we can guide you further and it will help out other people in the future also.
http://www.fixya.com/support/r6150077-basic_lcd_monitors_troubleshooting
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