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Digihome 32DLed906

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    Re: Digihome 32DLed906

    With the mainboard disconnected and the jumpers in place the secondary voltages should come up and also the backlights.

    Because I do not have the 25.1v on pin 1 of the driver input connecter.
    Isn't that also provided by the power supply so that to should come up with the jumper resistors in place.
    Last edited by dick_barton; 11-04-2017, 10:24 AM.
    Willing to help but I'm no expert.

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      Re: Digihome 32DLed906

      Yes it is provided by the power supply but it has not come up with the jumper in place and the main board connecter pulled, But it is their when jumper is off and main board connected ?

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        Re: Digihome 32DLed906

        I really do appreciate every ones help with this issue without all your input I would not have got this far.
        And I appreciate flocko's advice that one dry could cause the driver board to shut down.
        But having said that I was very careful when replacing all the LED's and made sure I seen the solder flow on each and every one when installed. now as you all know I mainly have worked on CRT's 20 + years ago so these LCD's and Plasma's are relatively new to me , and these LED's are new to me and to be completely honest this TV and the LG I recently worked on are the first LED's I have replaced.
        So you can understand I am not 100% confident with these flat panels and of course I will make some mistakes along the way admittedly some very stupid, some not so stupid.
        But if you could bare in mind when I post my results I probably don't always get it right And I may not completely know what I can and cannot do concerning Led backlights but I am slowly learning.
        But in no way was I taking a shot in the dark my thought was to eliminate each strip and the way I thought was to test each one not thinking I could cause any damage and of course this way was obviously the wrong way .
        What I also can't make sense of, is this LED tester the idea of having a LED tester at your side is so you can test the LED backlights and save the issue of having to strip a LCD panel completely down, but as flocko pointed out they do not work the same as a LED driver board and so therefore they would mislead you into thinking the Led backlights are working fine as they would still light up all the LED's even if some had dry joints or bad connections ?
        Sorry if I have waffled on a bit but I really do appreciate all the help you all are giving me thank you all very much.

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          Re: Digihome 32DLed906

          Any way back to this dick barton do you think I should remove the jumper set up, as this is not giving me the 25.1v to the LED driver board this voltage was present when the main board was connected to the power supply ?

          Comment


            Re: Digihome 32DLed906

            Can I ask what secondary voltages if any do you get with the mainboard disconnected and the two jumpers in place. +12, +24, +5STBY, +3V3STBY.

            If they are missing then one more connection. Connect Soft_Start Pin4 (PL805) to GND (Pins 1,3,5,7 or 9) as per the schematic on page 1 of this thread.
            Willing to help but I'm no expert.

            Comment


              Re: Digihome 32DLed906

              Does that connection need to be with a 1k resister ?

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                Re: Digihome 32DLed906

                on some sets, you do have to jump the dimming pin as well.
                WHY CAN'T PHILIPS USE PHILLIPS HEAD SCREWS?

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                  Re: Digihome 32DLed906

                  I may have the switching of Stby_On/Off backwards. Looking through previous threads on this power supply I found a drawing which would indicate that to power up the secondary supplies you need to do the reverse of what I was saying.

                  Can you give it a try and take Stby_On/Off to GND and see if the secondary supplies come up.

                  Initially we need to get the power supply secondary voltages up and running without the mainboard connected or worrying about the backlights at the moment.
                  Attached Files
                  Willing to help but I'm no expert.

                  Comment


                    Re: Digihome 32DLed906

                    So am I linking pin 6 to pin 14 with a 1k resister and also linking pin 6 to GND with a 1k resister ?
                    Last edited by ronhayes; 11-04-2017, 05:46 PM.

                    Comment


                      Re: Digihome 32DLed906

                      Or am I just linking pin 6 Stby_On//off to GND using a 1k resister ?

                      Comment


                        Re: Digihome 32DLed906

                        Sorry for"shot in the dark" pun, i thought it was funny , but let see if I can be more helpful, I dont think there is a problem with any of your boards (main /power and driver) but you will have if you try testing them the way you are. The driver board checks for over/under current, and if it see any will shut down, so stopping any risk of fire, so any change in LEDs (short/open) and the current they are drawing will shut the driver down, as you see a flash from the back lights we can tell that at least the driver is working, as is the main and power board. so where could the problem be, LEDs not of the correct size/ dry solder joint to strips/ connections in the wiring to the strips. I am not a fan of LED testers, as you have seen they can and will lead you down the wrong path. I do hope you find the fault with your set and that this will help you. Flocko

                        Comment


                          Re: Digihome 32DLed906

                          I believe that flocko is correct, however starting from the very beginning the 1K resistor between Pin6 and ground should bring up the secondary supplies.
                          If it does then a second 1K resistor from +5V to BL_On/Off should bring up the backlights.
                          If the backlight flash then it would still look like a led problem.
                          Willing to help but I'm no expert.

                          Comment


                            Re: Digihome 32DLed906

                            Is there any how to test the current draw the whole back light circuit is drawing then look at the led driver board specs?
                            flocko im still learning as well so when you say any change in leds (short or open) and the current drawing will shut the driver down, as all rons leds now light ok dose this rule out them being short or open? also in the above posts ron has rewired all the joints with wire so that must rule out a bad connection right back to the led driver board so that should also rule out a bad connection, i know ron has purchased these leds from proman on ebay who a lot of people have brought and used his led kits and he has 100% feed back so in theory the leds should be ok too? im still learning but ive also replaced every led in a set myself and its worked fine i didnt even have to bridge the connections so certainly a odd fault in this set.
                            Last edited by vinceroger69; 11-05-2017, 04:45 AM.

                            Comment


                              Re: Digihome 32DLed906

                              Linking pin6 to GND with a 1k resister has not brought up the secondary supplies ?

                              Comment


                                Re: Digihome 32DLed906

                                I have now removed the link wires from the Led strips, as I pulled the connection wires on that link driver board to strip connection board and closed the gaps on each wire connection each end. I then cleaned all Led strip connections on strip connection board with a fibre glass pen and tined with solder for a better connection due to strip boards being removed so many times. I now get backlights coming on after 5 seconds after switch on but still go out after a couple of seconds ?
                                I have also taken the time to replace the double sided tape on Led strips rather than the temporary measure of the tape I had put on ?

                                Comment


                                  Re: Digihome 32DLed906

                                  I am saying when you first come across a set with faulty LEDs that has a driver/power board shut down, then one or more shorted/open LEDs will be the problem(over/under current). So when replacing LEDs you must be mindful that they need to be of the same rating(size/ voltage/colour/and current consumed and allowed to pass)so you can see any LED that is under or over rated if you are replacing a large number will soon add up to be a problem, plus this being an older set that uses a power and stand alone driver board with only one LED string with 40 or more LEDs that problem is easy to see.On a later model that has a combine power/drivers with four or more strings of 10+ LEDs the need to match LED ratings becomes less of a problem (the models I talk of being 32")

                                  Comment


                                    Re: Digihome 32DLed906

                                    Thank you.
                                    I now understand a lot more about these backlight Led's and it makes sense ! I think now my only way to solve this is to replace these complete strips ? the problem being I have so far only seen one set being sold and they were about £40.00 I will do more of a search to see if I can locate some for a reasonable price ?

                                    Comment


                                      Re: Digihome 32DLed906

                                      Originally posted by flocko View Post
                                      I am saying when you first come across a set with faulty LEDs that has a driver/power board shut down, then one or more shorted/open LEDs will be the problem(over/under current). So when replacing LEDs you must be mindful that they need to be of the same rating(size/ voltage/colour/and current consumed and allowed to pass)so you can see any LED that is under or over rated if you are replacing a large number will soon add up to be a problem, plus this being an older set that uses a power and stand alone driver board with only one LED string with 40 or more LEDs that problem is easy to see.On a later model that has a combine power/drivers with four or more strings of 10+ LEDs the need to match LED ratings becomes less of a problem (the models I talk of being 32")
                                      Thanks flocko that makes sense to me now too now so lets just say we have sc led we look at the led strip numbers etc how do we tell the led specs used so we know what to replace them with? yes voltage and physical size is easy but what about the other specs needed and thanks for offering your knowledge and advise im sure it will help others reading this thread to.
                                      Last edited by vinceroger69; 11-05-2017, 05:55 AM.

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                                        Re: Digihome 32DLed906

                                        Ron I am glad I have helped with your understanding and anyone else that come across this post. One other thing I must say about replacing LEDs is that do not use s/hand LEDs from old strips and try to resolder as the heat cycle that is needed to remove and refit will see it fail in a short time(heat kills LEDs)it is better to cut and stack the strip.

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                                          Re: Digihome 32DLed906

                                          Yes you have helped and in future I think the stack method would be the safest way! I see now where I was going wrong.
                                          I do appreciate the help.

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