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WoR496
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Last Activity: 01-04-2011, 02:37 PM
Joined: 11-21-2010
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  • WoR496
    replied to Dell SE198WFPf - Backlights go off after 2 seconds
    in Troubleshooting Computer Displays
    Re: Dell SE198WFPf - Backlights go off after 2 seconds

    found the bad solder joint on one of the bulbs, re soldered but in the process i messed up the rubber that was covering it, so now it has carefully placed electrical tape around it lol, but to my surprise no arcing, no hissing or other sounds, and no lights going out. Silent as can be. I figured i'd get a spark show but for now all is good. Now if i can get it back together without messing it up in the process

    I appriciate the help very much from you all. If i post again i'll be sure bring a little more to the...
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  • WoR496
    replied to Dell SE198WFPf - Backlights go off after 2 seconds
    in Troubleshooting Computer Displays
    Re: Dell SE198WFPf - Backlights go off after 2 seconds



    sorry i've got myself tied in a knot and so much going on i forgot what all i did, but luckily i stumbled across something now that i have the ccfl's out of the display, one has a HV leak, touched the metal case and got a nice suprise. stuck the pos lead of my DMM on it and it started beeping and going nuts. I suppose this could cause the problems i'm having? I oppologize in advance for being a pain in the rear noob with this stuff, i really don't have a whole lot of experience with component level electronics...
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    Last edited by WoR496; 11-24-2010, 04:52 PM.

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  • WoR496
    replied to Dell SE198WFPf - Backlights go off after 2 seconds
    in Troubleshooting Computer Displays
    Re: Dell SE198WFPf - Backlights go off after 2 seconds

    more info.. voltage from transistors at 12 oclock and 1:30 locations looking from top of board. Don't know if this helps but it seemed odd that the one at 12oclock would do what it is doing when the ccfl's go out.

    12oclock transistor - when ccfl's are working normally
    1- ~3.2V
    2- ~16v
    3- ~3.2V

    12oclock transistor -when ccfl's go out and stay out
    1- Alternates between ~1.85V and ~2.35V
    2- Stays at ~19V
    3- Alternates between ~1.85V and ~2.35V

    1:30 transistor...
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  • WoR496
    replied to Dell SE198WFPf - Backlights go off after 2 seconds
    in Troubleshooting Computer Displays
    Re: Dell SE198WFPf - Backlights go off after 2 seconds

    well i resoldered the inverters and most joints in between it and the ccfl connectors, the first time i powered it up after that it did nothing different, went off after a couple seconds, but the second time i powered it up it stays on for about 1 min. then starts to kind of flicker, then shuts off. And this is repeateable.. but it seems that if i have the power board or wires just right it will only come on for the 1-2 sec again.
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  • WoR496
    replied to Dell SE198WFPf - Backlights go off after 2 seconds
    in Troubleshooting Computer Displays
    Re: Dell SE198WFPf - Backlights go off after 2 seconds

    I'm working threw the tests described in retiredcaps tutorial and so far nothing bad found. I did happen to locate a *hopefully* equivalent datasheet for this inverter controller chip. The one on the board is a OZ9937GN and this sheet is for an OZ9938GN so im not 100% sure of the difference but the package is identical. Datasheet attached, start on page 10, rest is gibberish.

    Never did troubleshooting on an IC before but i'm going to give it a shot lol, datasheet seems to give a decent picture of what exactly it...
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  • WoR496
    replied to Dell SE198WFPf - Backlights go off after 2 seconds
    in Troubleshooting Computer Displays
    Re: Dell SE198WFPf - Backlights go off after 2 seconds



    If i had known that what the link pertained to i might have paid more attention to its contents i thought it was supposed to be rules for the fourms but i didn't see any ( just skimmed over) so i didn't know that it was a link to your guide.. sorry.....
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  • WoR496
    replied to Dell SE198WFPf - Backlights go off after 2 seconds
    in Troubleshooting Computer Displays
    Re: Dell SE198WFPf - Backlights go off after 2 seconds

    thank you for suggesting that tutorial, looks great will try it. I got a decent picture....
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  • WoR496
    replied to Dell SE198WFPf - Backlights go off after 2 seconds
    in Troubleshooting Computer Displays
    Re: Dell SE198WFPf - Backlights go off after 2 seconds

    **edit** 1st character was an "O" not a zero..

    so the CCFL controller is OZ9937GN
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  • WoR496
    replied to Dell SE198WFPf - Backlights go off after 2 seconds
    in Troubleshooting Computer Displays
    Re: Dell SE198WFPf - Backlights go off after 2 seconds

    0Z9937GN is what it has for the ccfl controller, if you really want a pic i'll get it but its so small theres no way i could get a good pic of it.
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  • WoR496
    replied to Dell SE198WFPf - Backlights go off after 2 seconds
    in Troubleshooting Computer Displays
    Re: Dell SE198WFPf - Backlights go off after 2 seconds

    Also i failed to mention that maybe 1 out of 8 times when you turn it on, the backlights will come back on one more time for the 1-2 seconds, then shut back off and stay off. I thought it was kind of odd and should point it out.

    In case that made no sense (happens) i'll map it out simple.

    Power on, lights on(1-2 sec), lights off(1-2sec), lights back on(1-2sec), no more lights, power led stays blue, makes repetitive high pitch noise.

    I checked the voltage regulators on the logic board and...
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  • WoR496
    replied to Dell SE198WFPf - Backlights go off after 2 seconds
    in Troubleshooting Computer Displays
    Re: Dell SE198WFPf - Backlights go off after 2 seconds

    well i was messing with it more and using the limited testing tools i have ( a dvom lol) i'm pretty sure all caps are good. I did notice one thing though. After the bulbs go out, there is a repeating high pitch sound. I recorded it hoping someone here might have a clue what this would point to. forgive the quality, the sound was very quiet so i had to do some amplification & noise reduction.









    You have a PM...
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  • WoR496
    replied to Dell SE198WFPf - Backlights go off after 2 seconds
    in Troubleshooting Computer Displays
    Re: Dell SE198WFPf - Backlights go off after 2 seconds

    Guess i should test them lol just one question, there is no voltage on any of the pins that changes after the bulbs come on. The only thing that ever changes is the BLON goes from 0 to 3.33v and the bulbs light up, but just for a second or so, then they shut off. but the BLON voltage stays up so wouldn't this indicate that in fact the logic board could not be the cultprit because it is still providing a BLON signal to the power/inverter board. which the leads on my dvom were smaller, i'd just compare resistance between the...
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    Last edited by WoR496; 11-22-2010, 01:15 PM.

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  • WoR496
    replied to Dell SE198WFPf - Backlights go off after 2 seconds
    in Troubleshooting Computer Displays
    Re: Dell SE198WFPf - Backlights go off after 2 seconds

    Well it would appear that the video board is doing its job, at least with the BLON. It works. It appears to be pin 4. When its off, no voltage, hit the power button, and no voltage until the backligh lights up, then it jumps to 3.33v and stays there but the bulbs don't stay lit up.

    Here is the voltage readings i got on the other pins.

    1 - 0.03
    2 - 0.0
    3 - 2.92
    4 - 3.33 BLON
    5 - 0.01
    6 - 0.01
    7 - 4.95...
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  • WoR496
    started a topic Dell SE198WFPf - Backlights go off after 2 seconds
    in Troubleshooting Computer Displays

    Dell SE198WFPf - Backlights go off after 2 seconds

    Have a Dell SE198WFP 19" LCD Monitor. When turned on the back lights are on for about 2 seconds then they go off. There is still an image just no back lights. I've looked carefully over the power supply board (inverter board and ps board are integrated on this monitor), and i see absolutely no sign of bad caps, they all look great, no bulge at all or leakage. Could one still be bad without visible signs? I see many many posts elsewhere about people having the same problem with this monitor, but nobody ever posts if they find a solution.

    Oh and the monitor is not going into...
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