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17ips20 diagnosing

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  • Leslie W
    replied
    Re: 17ips20 diagnosing

    Hi Reece

    Thanks for your help, please bear with me I am just a beginner.

    Why does the led voltage start at 160+ then go to 118 if 36 x 3.3 leds = 118 volts ?

    with the leds unplugged voltage is 117.6 and zero on return

    Les

    Leave a comment:


  • ReeceyBurger123
    replied
    Re: 17ips20 diagnosing

    Unplug the Leds and check again, use chassis ground. Sounds like a Psu problem to me if it stays low. Also thats not enough for the Leds that voltage its enough to complete the chain but only light them dim.

    Leave a comment:


  • Leslie W
    replied
    Re: 17ips20 diagnosing

    Hi Guys

    Hitachi 42hxt12u with Vestel 17ips20 23145840 problem.

    TV made a crack noise and now no picture. No backlights but I can see menu with torch.

    Audio working and can change channels and sources.

    LED output from PSU is 117.7 return 8.3 when turned on - it does not go to 170 or 190

    Is this a psu or a led problem? Why arent the leds lighting if I have 118 volts for the 36 x 3.3v vor the leds?

    Leave a comment:


  • ReeceyBurger123
    replied
    Re: 17ips20 diagnosing

    Yes then you have a backlight fault then, the Psu is fine if it goes up then drops. Take the panel apart and test the Leds as shown in the video.

    Leave a comment:


  • crt man
    replied
    Re: 17ips20 diagnosing

    At start up the power goes to 190 before
    dropping back to 119 the negative goes
    to 24 then drops back to 11

    On standby the voltage on the positive drops
    to zero and the negative stays at 11

    Alan.

    Leave a comment:


  • ReeceyBurger123
    replied
    Re: 17ips20 diagnosing

    Wait on start up does the voltage go to about 170 or so then go down ? If it stays at 119 your Psu/driver is faulty.

    Leave a comment:


  • crt man
    replied
    Re: 17ips20 diagnosing

    Please verify if you have backlight or not, if you do not check the Led voltage,
    Reece, the backlight is out i hooked up a free view recorder
    and it switched to the scart.
    There was sound, and when turned to the window
    an image was visible

    The voltage for the LED's was 119 on positive and 11
    on negative.
    I have bought some Nos LED's from Ebay just waiting for
    them to arrive

    Alan.
    Last edited by crt man; 07-02-2016, 06:24 AM.

    Leave a comment:


  • ReeceyBurger123
    replied
    Re: 17ips20 diagnosing

    Well the Psu is good then, you have an Led failure probably. Watch this video:

    https://m.youtube.com/watch?v=RxwdC7V5Ue0

    Please verify if you have backlight or not, if you do not check the Led voltage, if that is good take the panel apart and check the backlights as shown in the video. Be very carefull with the Lcd screen and its attached Pcb they are easy to break and wont be fixable if so. Keep us updated
    Last edited by ReeceyBurger123; 06-30-2016, 07:06 AM.

    Leave a comment:


  • crt man
    replied
    Re: 17ips20 diagnosing

    Originally posted by ReeceyBurger123 View Post
    Cheers Vince, also what is the set doing totally dead ?
    Sorry Reece, I was told set did not work,
    as it had been standing in the rain I did not plug it in.
    Just plugged it in and led changes from red to blue
    but screen is black and no sound, I do not have the
    remote so it could be on an external source.

    Alan

    Leave a comment:


  • Andrew F. Ali
    replied
    Re: 17ips20 diagnosing

    If I may inject here....I have found that analogue meters detect 'leaky' semi-conductors more readily than digital meters. I have a trusty analogue on my workbench for testing semis

    Leave a comment:


  • ReeceyBurger123
    replied
    Re: 17ips20 diagnosing

    Cheers Vince, also what is the set doing totally dead ? You should check ehat voltage you have on the secondary diodes first see if you have 12v at the lower down ones then 12-128v at the ones near the top. If so then psu is good.

    Leave a comment:


  • vinceroger69
    replied
    Re: 17ips20 diagnosing

    im sure reece will reply when he sees this thread and advise you on the diode location

    Leave a comment:


  • crt man
    replied
    Re: 17ips20 diagnosing

    Hi
    Yes I have seen it but this has not blown up,
    and the are no obvious shorts.
    I assume it is the leaky diode he is talking
    about in P3

    Alan
    Last edited by crt man; 06-30-2016, 03:23 AM. Reason: Addition to post

    Leave a comment:


  • vinceroger69
    replied
    Re: 17ips20 diagnosing

    reece has a good video about this board not sure if you have saw it
    https://www.youtube.com/watch?v=x7vnoqcTbQM&app=desktop

    Leave a comment:


  • crt man
    replied
    Re: 17ips20 diagnosing

    Sorry Reece for hacking the thread,but I got a Hitachi
    40 inch Led from somebody's garden with the above PSU.
    Which is the leaky diode you mention,as there is no shorts
    on the FET's and the fuse is fine.

    I cannot see the diode you mention or I'am I just going
    senile with old age.

    Thanks Alan.

    Leave a comment:


  • ReeceyBurger123
    replied
    Re: 17ips20 diagnosing

    Normally there is a leaky not shorted diode right next to the filter caps. Remove it out of circuit and check it for continuity in both directions common issue on these boards. If the transistors fail they will blow the fuse.
    Last edited by ReeceyBurger123; 10-22-2015, 04:11 AM.

    Leave a comment:


  • zwarder
    replied
    Re: 17ips20 diagnosing

    There are kits available to repair

    http://www.ohmsupplies.co.uk/KIT377-...D13-REPAIR-KIT

    Probably pick up a second hand board cheaper though

    Leave a comment:


  • layad
    started a topic 17ips20 diagnosing

    17ips20 diagnosing

    hello guys
    i have led tv which has 17ips20 psu , the tv is completely dead , no lights at all, i have checked the all the diodes, they are all ok, all fuses are ok, anyone knows how to test Q301? the tv is jvc le-40dg51j
    thanks
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