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Thread: LG 42LC7D Query

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    Default LG 42LC7D Query

    Sorry to hassle you guys, I had, up until Boxing day a working 42LC7D tv and was very happy with it but after only 3 1/2 years of use it has died and is of course, out of warranty. I checked the power supply, replaced all capacitors with the correct (as far as I know anyway) low ESR replacements but the fault didn't change. I paid for and downloaded the service manual which seems a little vage compared to most manuals I posess but I guess it's the way it is these days. The symptom is no picture, no sound, no menu's etc. but I do get a flash of "pink noise" (if that's the right word for it) and a burst of sound if I press the pushbutton on the main board but the manual dosen't explain what this is for, a reset I suspect??
    The cpu board seems to be on as such as it turns on and off with the remote, the backlights fire up, apart from no display it seems operational.
    The only measurement on the power supply that are out of spec are pin 5 on P1500, showing 6.3V as opposed to 6.5 and pin13 on P1501 shows 1.79V instead of the 3.4 required and this seems to be the cpu board feedback (power good?) signal to the power supply.
    Any suggestions and ideas would be greatly appreciated.

    Best Regards - Tony Eagling Vk7YBG



Look Here ->
  • #2
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    Hi Monkey Man, Can you post up the full product code, this includes a bunch of letters after the model number and I'll have a look at my manuals.



    Mickstv

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    Thanks for the help so far Mick, the chassis No# is 42lc7d-ab.aauvlh. Any service bulletins, advice etc would be great. I traced the 3.4v "on" feed back to pin 40 on IC1402 but without knowing more about the theory of operation I am stumped. I did notice a few smd caps on the board that have poor esr readings but have yet to replace these although I don't think they are related to the fault either. Do these cpu's etc "lose their minds" and if so is there a reset procedure for them apart from pushing pb300? I wonder if my psu is still problematic and is it worth getting one to try? Sorry to be a pita but I paid $1,800 for this TV and I feel it is poor value for money to only get 3 1/2 years out of it.
    Also, maybe stupidly, prior to finding this forum I replaced this TV with another LG, a led backlit 42LE4500-TA, hopefully a more reliable machine in the long run.

    Best Regards - Tony Eagling Vk7YBG

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    No worries just having a look now.



    Mickstv

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    Looks like the problem is either a software lockup caused by write error on an eprom or you'll need a new Mainboard. I'll see if I can get the software for you.




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    Thanks Mick, I look forward to trying ANYTHING with this damned thing to get it going again, a new/secondhand board if it comes down to it and the price is right is ok too.
    Has anyone got a set of Psu and main boards from one with a dead TFT??

    Best Regards - Tony Eagling Vk7YBG

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    For some reason I can't download the firmware update file. Looks like I'm locked out of downloading updates for some reason. I've been onto tech support and are going to get the problem fixed.


    This is the story
    ---------------------------------------------------------------------------------------------

    Please Note: Factory has released software to correct issue below:
    When operating in RGB mode possibilty arises that Eeprom data corrupted and will cause
    Lockup latch problem with IC101..
    This will then cause No VIDEO and AUDIO on ALL inputs with Minor Remote operation and render LCDTV inoperable..
    No OSD or servcie Mode operation:
    ONLY BACKLIGHT operational.
    :::TO RECOVER FROM THIS PLEASE UPLOAD NEW SOFTWARE FILES ATTACHED FOR RELEVANT MODEL:
    DUE TO LOCKUP OF TV YOU MUST USE THE FORCED DOWNLOAD METHOD ..
    [Download method in the latch-up state]

    1.Power off TV set.
    2.Connect PC with TV set by RS-232C serial cable.
    3.Execute ?DTV-Lab? program or another RS-232C debug-program, and set baud-rate to 115,200 bps.
    (For connection and baud-rate setting, refer to the usage of RS-232C debug tool applied to the other models)
    4.With pressing the number key ?1? of PC keyboard, power on TV set.
    5.After you check the message to be ready to download, select a file to send (or download).
    6.If download process (including programming flash-ROM) is finished, TV set will be rebooted automatically.

    -------------------------------------------------------------------------------------------





    Mickstv
    Last edited by mickstv; 04-01-11 at 03:09 PM.

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    Quote Originally Posted by Monkey Man View Post
    Thanks Mick, I look forward to trying ANYTHING with this damned thing to get it going again, a new/secondhand board if it comes down to it and the price is right is ok too.
    Has anyone got a set of Psu and main boards from one with a dead TFT??

    Best Regards - Tony Eagling Vk7YBG

    Forgot to mention I do have boards for that model they came out of a set with a broken screen but the boards still work.

    If you wan't me to send over the Tuner/Main board PM be your details and we can also decide a reasonable price ok.




    Mickstv
    Last edited by mickstv; 04-01-11 at 03:32 PM.

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    Quote Originally Posted by mickstv View Post
    For some reason I can't download the firmware update file. Looks like I'm locked out of downloading updates for some reason. I've been onto tech support and are going to get the problem fixed.


    This is the story
    ---------------------------------------------------------------------------------------------

    Please Note: Factory has released software to correct issue below:
    When operating in RGB mode possibilty arises that Eeprom data corrupted and will cause
    Lockup latch problem with IC101..
    This will then cause No VIDEO and AUDIO on ALL inputs with Minor Remote operation and render LCDTV inoperable..
    No OSD or servcie Mode operation:
    ONLY BACKLIGHT operational.
    :::TO RECOVER FROM THIS PLEASE UPLOAD NEW SOFTWARE FILES ATTACHED FOR RELEVANT MODEL:
    DUE TO LOCKUP OF TV YOU MUST USE THE FORCED DOWNLOAD METHOD ..
    [Download method in the latch-up state]

    1.Power off TV set.
    2.Connect PC with TV set by RS-232C serial cable.
    3.Execute ?DTV-Lab? program or another RS-232C debug-program, and set baud-rate to 115,200 bps.
    (For connection and baud-rate setting, refer to the usage of RS-232C debug tool applied to the other models)
    4.With pressing the number key ?1? of PC keyboard, power on TV set.
    5.After you check the message to be ready to download, select a file to send (or download).
    6.If download process (including programming flash-ROM) is finished, TV set will be rebooted automatically.

    -------------------------------------------------------------------------------------------





    Mickstv
    OK, I feel stupid now, I did forget to mention I shut the telly off whilst it was in RGB mode, it would seem the software is indeed the bugbear...
    You Da Man Mick!!
    I will however reserve the right to grovel at your feet and to feed your wallet a bit for a board from you if the file does not work....

    Best Regards - Tony Eagling Vk7YBG

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    Just sent a private message mate.




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    Awesome, Worked a treat, TV is 100% functional again!!
    Many Thanks.....

    Best Regards -Tony Eagling Vk7YBG
    Last edited by Monkey Man; 04-01-11 at 10:29 PM.

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    Quote Originally Posted by Monkey Man View Post
    Awesome, Worked a treat, TV is 100% functional again!!
    Many Thanks.....

    Best Regards -Tony Eagling Vk7YBG


    No worries and hope to see you buzzing around on the forum helping other people with your knowledge.


    Mickstv

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    Default Lg 42lc7d-ab

    I am after the updated software for this model as i have the no sound no picture problem if you could help me please

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    I could send you this software but I am not sure as to wether or not it is what you require, I am sure Mick will chime in and have you sorted in no time.

    Regards - Tony Eagling Vk7YBG

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    ok thanks tony
    shayne
    vk3tvv

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    Hi shayne, I would suggest if you haven't already check for bulged caps in the powersupply.




    Mickstv

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    hi guys,

    i have this exact model TV and ever since I've had it, the sound cuts out for like 1sec every 5-10mins intermittently. The TV originally was upstairs using rabbit ears and always thought it was due to the poor reception but now that I've got it downstairs on the main antenna and hooked up to my PS3, it still does the same thing and now the TV is out of warranty. From my knowledge, I'm guessing its a firmware issue? Can anyone help at all?

    The exact code of the TV is 42LC7D-AB.AAUVLJD

    many thanks,
    chiev

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    i have measured the power supply and viewed and found it to be ok.
    thanks
    shayne

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    Quote Originally Posted by shyane View Post
    i have measured the power supply and viewed and found it to be ok.
    thanks
    shayne

    Shayne do you use the RGB mode on the LG because it's only that input mode that causes the unit to lock up. Now if that is the case it most likely it will be the upgrade. I don't have the file handy today because I'm not at work but if you PM Tony he might send it to you and tell you how to do it.




    Mickstv

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    PM Me shayne and I'll get the files and instructions to you...

    Regards - MM

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