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obix
Chip Head
Last Activity: 03-04-2019, 12:05 AM
Joined: 02-01-2016
Location: 59104
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  • obix
    replied to LG 42LC7D-UK Repair
    in Troubleshooting TVs and Video Sources
    Solved!

    YOU GUYS ROCK!!!

    The U501 chips showed up today, I ordered two in case I burnt one. Got out the rubber gloves, hair net, and a fresh beer and soldered it on. Pin#6 now reads 12.39 Vdc and on connector P201#3 I now have a 5 Vdc stand-by voltage. I re-connected all the cables and tried it out... works great!

    I'll put some hours on it to be sure I got everything but I think it's whipped. Thanks so much, I'm sure I'll be back again, hopefully with more to offer then just with my hand out.

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  • obix
    replied to LG 42LC7D-UK Repair
    in Troubleshooting TVs and Video Sources
    Re: LG 42LC7D-UK Repair

    Thanks Vince, yes I had missed that edit. Yes, I am running the SMPS board with only the AC main connection. I'm ordering the above mentioned IC from Mouser, hope it comes soon.
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  • obix
    replied to LG 42LC7D-UK Repair
    in Troubleshooting TVs and Video Sources
    Replacement for U501

    Do you think this one from Mouser would work as a replacement? [URL="http://www.mouser.com/ProductDetail/ON-Semiconductor/NCP1230D65R2G/?qs=sGAEpiMZZMtqO%252bWUGLBzeBr9ESHqaeEC"]LINK[/URL]

    It looks like the same think.

    Also, when removing U501 I ruined the trace pad for Pin#1, It doesn't look like it connected to anything, the datasheet says it's a direct connect to Pin#6. With two magnifying glasses and three flashlights it appears as though Pins 1 & 7 are both N/C.

    I'm wondering if this board is too hosed...
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    Last edited by obix; 02-07-2016, 05:05 PM. Reason: Updated information

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  • obix
    replied to LG 42LC7D-UK Repair
    in Troubleshooting TVs and Video Sources
    Re: LG 42LC7D-UK Repair

    Ok, I'll see if I can get a replacement U501 from Mouser or Digikey, I'll post back with results. Thanks again so much for the help!
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  • obix
    replied to LG 42LC7D-UK Repair
    in Troubleshooting TVs and Video Sources
    Re: LG 42LC7D-UK Repair

    I replaced C507 with a 47uf/50V but still no change in the voltage levels on IC U501 Pin#6...

    Also, there is no voltage at P201 / #3, actually I don't get a voltage reading on any of the pins on P201 thru P206.
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    Last edited by obix; 02-07-2016, 01:45 PM. Reason: Updated information

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  • obix
    replied to LG 42LC7D-UK Repair
    in Troubleshooting TVs and Video Sources
    Re: LG 42LC7D-UK Repair

    Ok, C507 is bugging me. I just tested out of circuit on my DMM, which only goes up to 20uF, and it climbs above this, I swear it reads ".47uF" but it MUST be a "47uF". In which case it's definitely bad. So I'll replace this and see what happens.
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  • obix
    started a topic LG 42LC7D-UK
    in Albums

    LG 42LC7D-UK

    Repair: This unit has no power, no LED.
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  • obix
    replied to LG 42LC7D-UK Repair
    in Troubleshooting TVs and Video Sources
    Re: LG 42LC7D-UK Repair

    I pulled and tested D205 also, it seems fine. It's a STPS20H100CT.

    So I guess the question right now is why isn't Pin#6 on U501 reaching the 11.6 Vdc?

    I'll start on the other possibilities you mentioned in post#4 tomorrow, thank you so much for youCan't never could do nothin' r help on this one, it is very appreciated!
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    Last edited by obix; 02-07-2016, 12:58 AM.

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  • obix
    replied to LG 42LC7D-UK Repair
    in Troubleshooting TVs and Video Sources
    Re: LG 42LC7D-UK Repair

    I pulled and checked caps with ESR:

    C505 22uF / 50V = 0.41
    C507 0.47uF / 50V = 3.7 ( strange this cap is larger then C505 but I'm sure there's a decimal on it )

    Wish I had the schematic and parts list for this board... I'll check the diodes next.
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  • obix
    replied to LG 42LC7D-UK Repair
    in Troubleshooting TVs and Video Sources
    Re: LG 42LC7D-UK Repair

    Here are the results using pin#4 as the GND:

    Pin#6 = 8-10.3 Vdc
    Pin#8 = 164 Vdc

    Would you say that this means that startup voltage at pin#6 is too low? What happens if I give it a little boost to see if it will start?
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  • obix
    replied to LG 42LC7D-UK Repair
    in Troubleshooting TVs and Video Sources
    Part# U501

    I'm finally getting back on this LCD. I got a close-up of ic U501, it is a NCP1230D6, which is a 'Low−Standby Power HighPerformance PWMController'. Here is a link to the [URL="http://documents.mx/download/link/230d6-lowstandby-power-high-performance-pwm-controller"]DATASHEET[/URL]. I'll try getting some measurements then post them.Part# U501

    I'm finally getting back on this LCD. I got a close-up of ic U501, it is a NCP1230D6, which is a 'Low−Standby Power HighPerformance PWMController'. Here is a link to the [URL="http://documents.mx/download/link/230d6-lowstandby-power-high-performance-pwm-controller"]DATASHEET[/URL].    ...
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  • obix
    replied to LG 42LC7D-UK Repair
    in Troubleshooting TVs and Video Sources
    Re: LG 42LC7D-UK Repair

    Thank you for the help budm. Yep this is the same one, I'm following those threads also thanks. I'll be heading back to the my bench soon and will focus on the standby and the other areas that you listed. I pulled and tested Q501 earlier, it's good, so I bet you are right on with IC U501.

    Hopefully I will have some useful info to contribute to the forum very soon.

    P.S. - The display had been coming on previously and was staying on until turned off, however after it was turned off it would not come back on...

    Also, when...
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    Last edited by obix; 02-02-2016, 09:03 AM.

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  • obix
    replied to LG 42LC7D-UK Repair
    in Troubleshooting TVs and Video Sources
    Re: LG 42LC7D-UK Repair

    Thanks Caleb, yep actually I do have that one. It's for the -AB subversion and only has the partial schematic for the Main board which is different. However, I believe that the Power board is the same but they don't give the schematic for that... It's the LG EAY32731102 ( FSP286-6F02 ), this is a 2008 model.
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    Last edited by obix; 02-02-2016, 12:00 AM.

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  • obix
    started a topic LG 42LC7D-UK Repair
    in Troubleshooting TVs and Video Sources

    LG 42LC7D-UK Repair

    I just put this model on my bench this week, a LG 42LC7D-UK. I replaced all the caps on the SMPS, and stuck a 6.8ohm/2W resistor in for R109, it was a thermo fuse/resistor. Now this unit is dark, not even red/green led on front... I'm going to mess with pulling the PWR_ON high with some batteries and pull and check all the MOSFET's on the power board next. I've got clean power through the second iso-transformer, and 165Vdc off of rectifier... There does not seem to be any power on any of the outgoing connectors.

    I've gotten the service manuals for the -AB and -UB versions but can't...
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    Last edited by obix; 02-01-2016, 11:53 PM. Reason: Updated information
  • obix
    replied to LG 42LY95 Help identify components.
    in Troubleshooting TVs and Video Sources
    Re: LG 42LY95 Help identify components.

    Not sure if the image is going to come up in the post so I'll also attach a copy.[ATTACH]126694[/ATTACH]...
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  • obix
    replied to LG 42LY95 Help identify components.
    in Troubleshooting TVs and Video Sources
    LG 42LY95 Help identify components.

    I know this is an older post but I'm currently working on this unit so I thought I'd add this information. The component R109 is a Thermal Cut-off Resistor or Fuse, it's a RCT051S / 6R8. Here is a link to the [URL="http://www.raraohm.com/catalogues/rara_RCT%20Rev.%202008-12-11.pdf"]DATASHEET[/URL].
    This is an image of the bad one I pulled out. Not having one on hand I temporarily am testing it with a 2W 6.8ohm resistor in series with a glass fuse.


    Hope this is helpful for someone. What I could really use...
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