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Proscan 32LB45Q No video or sound

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    #1

    Proscan 32LB45Q No video or sound

    Hi this is my first post here and I hope I can give out the most accurate information possible.

    Power supply board AYP418101 Rev. 1.0

    I have a proscan 32LB45Q with no video or sound like and I am getting odd voltage readings from the power supply. I am getting anywhere from 45 - 48 volts on con5 where I should be getting 24 volts respectively. Also I noticed that Con3 the wire color coding is reversed and is that part of the issue. My brother told me that the tv was functional, but I'm not sure if he tried to repair it before I had a chance to look at it myself.

    From what I have researched so far, most suggest just replacing the power supply. I am curious as to why this is occurring, and I would like to thank you in advance for any feed back you can provide.

    PS I have taken additional photos if those are not clear enough.
    Attached Files
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    #2
    Re: Proscan 32LB45Q No video or sound

    Originally posted by Markw959 View Post
    I am getting anywhere from 45 - 48 volts on con5 where I should be getting 24 volts respectively.
    1) Are you measuring AC or DC in the above?

    2) What you are you using a ground reference when measuring the above?
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      #3
      Re: Proscan 32LB45Q No video or sound

      Thanks for your quick reply and I am sorry I have only just now responded. To answer your questions. I checked the voltage in DC using a Velleman DVM850BL.
      I used the ground pin on same connector that I checked the voltage on. I made sure the power supply was still grounded to the TV chasis.
      I figured since I had a mishap on the TV and shorted the bridge rectifier I would just order a
      new power supply since I cant find a service manual on this model..

      Comment

        #4
        Re: Proscan 32LB45Q No video or sound

        Seems the cable for CON3 is backwards. When you measured the voltages, did you have it connected to the rest of the TV ?

        Comment

          #5
          Re: Proscan 32LB45Q No video or sound

          Well now I just got in the replacement power supply off of Ebay and I get 5vsb (5.13vdc) to be exact and 2.73vdc on the PS-On pin of con4. Connector 4 has 13 pins. pins #1 and #2 (12v) listed on the board I get no voltage at all. Pins #3 to #5 are ground. Pin #6 is 5v
          .02vdc actual; Pin #7 5v .02vdc actual; Pin #8 5vsb 5.13vdc; Pin #9 PS-ON 2.73vdc; Pin
          #10 5v .0v; Pin #11 5v 0v; Pins 12 & 13 are ground.
          I have noticed when I plug the set in there is a faint squeal coming from the PSB, the sound rises and falls sort of like a pulse, it continues until I cut the power.
          Any help you can give me will be much appreciated.

          Comment

            #6
            Re: Proscan 32LB45Q No video or sound

            I agree with you the wires look backwards, but CON3 idiot proofed so you can only plug the cable in one way.

            Comment

              #7
              Re: Proscan 32LB45Q No video or sound

              and the other tip of the cable , if you use that then the markings match ? The psus on the D-Link DGS 1248T have that "feature" .

              Comment

                #8
                Re: Proscan 32LB45Q No video or sound

                No voltage on con3? - Can you go through the complete start sequence, with a known source - dvd or pc is best- from plugging in switching on to a stable fault stage. What does the panel do - anything? what do the leds do? any sound - you have already mentioned the squeel. When you tried it were ALL cables connected.
                Please upload pictures using attachment function when ask for help on the repair
                http://www.badcaps.net/forum/showthread.php?t=39740

                Comment

                  #9
                  Re: Proscan 32LB45Q No video or sound

                  Well here's the latest on where I'm at with this TV. I went through the process of connecting CON4 to the mainboard again. Once I turned on the set, I got a red LED only on the front panel. I then powered on the set. I actually got the normal voltages on all connectors. CON4, CON3, and CON5.

                  My next step involved connecting CON5 back to the back light inverter. I turned on the set and it powered the screen for 5 seconds or so. The screen flickered and there was a
                  high voltage squeal before the screen went black, but the LED remained blue. Since I have had no luck finding the manual for this my brother looked on line at actual screen shots of this TV. It turns out that the cable I thought was supposed to go to CON3 is intended for J36 [24v/24v/GND/GND] on the main board. I then took the main board off the TV set to verify that J36 and not J16 (Speakers) was the correct jumper. I hooked everything up and turned on the set.. The screen flickered and the set went out completely. So now I'm starting over from square one on the power supply to see what went out. I'm confident I can repair the PSB again, but I'm totally confused on why the main board would short out the power supply.

                  Now I know why my father says never jump in on a project somebody else already started. You have no idea what they did or switched around...

                  Well any insight as always is appreciated..

                  Comment

                    #10
                    Re: Proscan 32LB45Q No video or sound

                    Originally posted by Markw959 View Post
                    CON3 idiot proofed so you can only plug the cable in one way.
                    Famous last words then?

                    Start again - we need really clear pictures of the boards
                    We can help a lot more if you please post good clear pictures of the whole chassis, and then pictures of each board, front and back and close up of connectors, (max resolution 2000x2000 and 2MB) using the manage attachments button, which is found by clicking "go advanced" under quick reply.
                    Examples of what is needed
                    https://www.badcaps.net/forum/attach...1&d=1290283049

                    https://www.badcaps.net/forum/attach...7&d=1280167246

                    Then set it all up with the correct cables the correct way around in the correct sockets then double check.
                    Post readings on the connectors.
                    Please upload pictures using attachment function when ask for help on the repair
                    http://www.badcaps.net/forum/showthread.php?t=39740

                    Comment

                      #11
                      Re: Proscan 32LB45Q No video or sound

                      Necesito el manual de servicio de esta fuente alquien la tiene o sabe donde puedo conseguirla..

                      Comment

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