We have a computer we brought back from a satellite office that has been in use for about 5 months. The LCD 17" monitor (BenQ FP731) and the computer have been plugged into a APC 500VA UPS for the entire duration. Prior to this move, they have worked just fine, together. When I plugged the PC in and turned it on here at the main office, the green monitor light comes on, briefly shows the POST screen then shuts off. If I turn the monitor off and back on, I can see the Windows XP logon screen briefly before the monitor shuts off again. I can power off and turn it back on and the screen displays briefly (about 1 second) then shuts off. I have tried this monitor on other PC's and it does the same thing. I'm at a loss at this point. It's not that old and has worked flawlessly until this point. Any thoughts on what else I can try? The video card works great with other CRT's we have (I haven't dared pull a working LCD off one of the other PC's as they'll come at me with knives :)
Did an independent diagnosis before finding this, and came to same conclusion. First found fuse PF751 was open circuit (3A black plastic fuse, not glass) over close to main heat sinks. When I replaced that with a fine fine strand of wire (for testing) then I saw Q759 (C5707) get hot. Checking the others shows that they should be driving into about 420 ohms on the primary side of the transformer for the flourescent lights (backlights) but on this one it was less than 1ohm. I've unsoldered the Q759 and now I measure 420ohms here too. Now I need to find a new C5707 or equivalent...
I had the same problem with a benq fp731 (same board as the 737), replaced the 4 c5707's (little black 3 legged transistors, they look like upright FET's, next to the little beige colored box shaped caps) and it fixed it.
Hi. i had the same problem and fixed it. the problem are the 4 transistors (C5707) one of more are shorted (Q739,Q740 and Q759, Q760). Also the fuse PF751 (3a) has to be replaced in most cases. In my case i replaced the fuse and 1 transistor (C5707)
Dear friends,Thenks a lot.Your forum help me for ripear my monitor. you are the great! Thenks! Kiro.biro
Hello, the same thing happened to me, my problem seems to be one of the 4 transistors c5707 (in some cases could be more if not all of them), and the 3 amp fuse, now where can you get this parts from? I dunno if my lcd is under warranty, it was a "u-fix-it--it's-yours" gift.
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It is probably the backlight inverter that has gone bad, it drives the CCFL lighting for the lcd screen. This model has a Inverter/powersupply combinatin board and are extremely hard to find replacements for.
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You are the only one to reply to my problem. :(
As soon as I find out, I'll post a solution, if nobody else here can contribute.
I turned on the monitor and connected it to a PC. When I shine a flashlight on the face of the monitor there is nothing, leading me to believe this is a power supply issue as you suggest. Do you know of any sources I can check to purchase a replacement for this? The monitor is just barely a year old and what does appear for that 1/2 second is crisp and sharp, leading me to believe it's worth saving.
I contacted BenQ about this issue. They have the same conclusing. The problem appears to be an inverter/power supply issue. It also appears the the monitor is under a 3 year warranty and they will repair :)
THanks for your help with this! You were right on the money.
Now if there was only a place for these parts...
I have the identical problem with my FP731 monitor. Is this fix a costly thing to do? Might be better off to buy a new monitor if it's too expensive parts and labor wise.
I have the exact same problem. My monitor is about 3 years old. I need to find out if i am still in warranty.
Hi,
My BenQ T705 monitor went blank and took my computer to the repair shop and it worked fine with the other monitor. Is there an easy fix? When I turn the monitor on, I see BenQ briefly and disappears.
I would appreciate any sort of help related to this problem.
Thanks,
Mani
I had the same problem and am trying to fix it with the solutions posted here. I found one of C5707 was shorted out. Anyway, I replaced all 4 C5707s and the FP751. But i didn't fix the problem. Any other suggestions? Please help!
Jin
Mine does exactly the same. Comes on for only a second and goes off again. Tried on my other computer - does the same there. I am just out of my guarantee.
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