Insignia NS-37D20SNA14 no power.

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • Spork Schivago
    Badcaps Legend
    • Mar 2012
    • 4734
    • United States of America

    #1

    Insignia NS-37D20SNA14 no power.

    Hello,

    I have an Insignia NS-37D20SNA14 that isn't turning on. There's no standby light or anything. I check the fuse and it's bad, so I replace it. It was a 15A 250V round red plastic fuse, but I replaced it with a 15A 250V square red plastic fuse.

    There's still no standby light. I check the caps with an ESR meter, they test good.

    Then I lift a leg on the four general purpose plastic rectifiers. I tested them like you would a diode. Not sure if that's right or not. I thought they were diodes. They're Vishay 1N5407's. With a leg lifted though, the continuity is different for certain ones, which makes me wonder if they're bad. I solder them back into place and hook the power supply board up. Then I try powering it on.

    I take the DMM and set it to VDC. I check the voltage on them, like I'd check a diode. Some don't have any voltage leaving at all. Not sure if that's proper or not. I used the ground coming in from the AC line as a ground source.

    Would they be bad? They're the ones in DSC01948, in the top left. I also lifted the heat sinks and checked the components under there (MOSFETs and Diode arrays or whatever they're called) and they tested fine.

    I tried checking to see if there was 12V on the connector where it's labeled 12V. I got nothing. I tried checking to see if there was 55V on the connector for the LED backlighting, nothing.

    Thanks!
    Attached Files
    -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full
  • dskall
    Badcaps Legend
    • Oct 2016
    • 2905
    • usa

    #2
    Re: Insignia NS-37D20SNA14 no power.

    What's voltage on main cap
    I assume no responsibility for any stupid suggestions I might post.

    Comment

    • dick_barton
      Badcaps Legend
      • Aug 2015
      • 6643
      • Wales

      #3
      Re: Insignia NS-37D20SNA14 no power.

      You do mean 1.5 Amp and not 15 Amp don't you! The diodes when lifted should really all read the same. I would replace them if they don't. They are general purpose 560V (800V peak) 3 Amp diodes.
      Do you have any dc voltages on the white connectors?
      Last edited by dick_barton; 06-11-2017, 03:38 PM.
      Willing to help but I'm no expert.

      Comment

      • Spork Schivago
        Badcaps Legend
        • Mar 2012
        • 4734
        • United States of America

        #4
        Re: Insignia NS-37D20SNA14 no power.

        Originally posted by dick_barton
        You do mean 1.5 Amp and not 15 Amp don't you! The diodes when lifted should really all read the same. I would replace them if they don't. They are general purpose 560V (800V peak) 3 Amp diodes.
        Do you have any dc voltages on the white connectors?
        I thought 15AMP was insanely high, but when I read the fuse, it doesn't say 1.5AMP. It says:
        Code:
        T3, 15A 250V
        382
        Here's exactly what it looks like. Maybe it's rated current 3.15A?

        The white connectors where the various wires hook up to? No, but I didn't check the PWM pin. So, how does the logic board turn the PSU on? I don't see a PS_ON. Does it involve the PWM pin somehow?

        Here's the Vishay Diodes:

        https://www.digikey.com/product-deta...GICT-ND/190144

        Are they a good brand name or should I try purchasing a better one?

        Thanks!
        Attached Files
        -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full

        Comment

        • Spork Schivago
          Badcaps Legend
          • Mar 2012
          • 4734
          • United States of America

          #5
          Re: Insignia NS-37D20SNA14 no power.

          Originally posted by dskall
          What's voltage on main cap
          Which one is the main cap? That big one that's off by itself or those two big ones next to each other? How should I reference ground? Just black probe on the cathode side or should I reference chassis ground or something?

          Thanks!
          -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full

          Comment

          • dick_barton
            Badcaps Legend
            • Aug 2015
            • 6643
            • Wales

            #6
            Re: Insignia NS-37D20SNA14 no power.

            The boards are often poorly marked and I would be looking at 1.5A rather than 15A which would probably vaporise your components if there was a short. However looking up the board on google it's a T3.15A fuse.
            Attached Files
            Willing to help but I'm no expert.

            Comment

            • Spork Schivago
              Badcaps Legend
              • Mar 2012
              • 4734
              • United States of America

              #7
              Re: Insignia NS-37D20SNA14 no power.

              Originally posted by dick_barton
              The boards are often poorly marked and I would be looking at 1.5A rather than 15A which would probably vaporise your components if there was a short. However looking up the board on google it's a T3.15A fuse.
              Thanks. Yeah, that's the conclusion I came to, a slow-burn T3.15A fuse. Just so happens the square one I put in had the same markings and shows as a slow-burn T3.15A fuse as well, so I think I'm good there.


              I found two new 1N5400's in the basement. Too bad I couldn't use them, but I see they're rated for 50VDC, not 800VDC, like the 1N5407's. Looks like I'm going to have to order some 1N5407's.
              -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full

              Comment

              • Spork Schivago
                Badcaps Legend
                • Mar 2012
                • 4734
                • United States of America

                #8
                Re: Insignia NS-37D20SNA14 no power.

                Originally posted by dskall
                What's voltage on main cap
                For C625 (the 250V 47uF capacitor), with reference to the AC gnd, it's 0VDC. With reference to the capacitors gnd (the black probe on the cathode side), it's 0VDC.

                I think I'm going to recap this PSU while I'm at it. Gonna start looking for new caps on digikey.
                Last edited by Spork Schivago; 06-11-2017, 04:41 PM.
                -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full

                Comment

                • Spork Schivago
                  Badcaps Legend
                  • Mar 2012
                  • 4734
                  • United States of America

                  #9
                  Re: Insignia NS-37D20SNA14 no power.

                  So I'm going through the caps. I see Mouser has a Nichicon 4.7uF 50v electrolytic cap ( http://www.mouser.com/ProductDetail/...wHjdTenA%3d%3d )

                  80mA for rated ripple current, 10,000 hours at 105c. Leakage current is 3uA. It's a ULD series. I think that would make a good choice for this TV, don't you? They're only 17 cents a pop....
                  -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full

                  Comment

                  • Spork Schivago
                    Badcaps Legend
                    • Mar 2012
                    • 4734
                    • United States of America

                    #10
                    Re: Insignia NS-37D20SNA14 no power.

                    These are the caps I ordered:

                    C510 -- http://www.mouser.com/ProductDetail/...wHjdTenA%3d%3d

                    C511 -- http://www.mouser.com/ProductDetail/...jtfSZwRA%3d%3d

                    C625 -- http://www.mouser.com/ProductDetail/...HFGGh%252bM%3d

                    C523, C524, C525 -- http://www.mouser.com/ProductDetail/...54ZssHrQ%3d%3d

                    C506, C507 -- http://www.mouser.com/ProductDetail/...2bSKyFA4BK8%3d

                    C521 -- http://www.mouser.com/ProductDetail/...52b7ehMA%3d%3d

                    C518, C519, C530 -- http://www.mouser.com/ProductDetail/...zZq52AGQ%3d%3d

                    D501, D502, D503, D504 -- http://www.mouser.com/ProductDetail/...RnVkhRo1AWo%3d


                    What do you guys think? Sorry for all the links, but this way, you guys can check out all the specs instead of me trying to figure out what specs you want to see and what ones you don't want to see.

                    C506 and C507 have a max ripple current rating of 860 mA. C625 has a max ripple current rating of 1,290 mA.
                    Last edited by Spork Schivago; 06-11-2017, 06:23 PM.
                    -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full

                    Comment

                    • Spork Schivago
                      Badcaps Legend
                      • Mar 2012
                      • 4734
                      • United States of America

                      #11
                      Re: Insignia NS-37D20SNA14 no power.

                      I've replaced the general purpose plastic rectifiers (diodes). Then I went and replaced the other diode I didn't notice earlier. Finally, I replaced all the caps. I checked every single one of the old ones for ESR and capacitance, they all fall within respective ranges.

                      One of the new caps I got has an ESR of something like 0.20, but the old cap has a lower ESR, like 0.02 ohm. Is this going to be a problem? In the first picture in Post #1, it's the far upper right one, the one that's all by itself.

                      Anyway, the television turns on now. So I'm wondering if I should attempt to gain access to the LED strips and resolder them. I believe this television has problems with the strips having been poorly soldered. I've never attempted anything like before and would like a good idea of what I'm looking at. Is it difficult, extremely hard, fairly easy, does it take a lot of time? I'd rather do the repair properly, rather than give it back just for it to break again.

                      I wonder why my DCA meter doesn't detect those general purpose plastic rectifiers as faulty. The DMM shows they do block electricity one way, but the resistance varies greatly when I measure it the other. The new ones all show around 6Mohms. Some of these old ones show around 6, around 4, and 0.2Mohms or something low like that.

                      Thanks guys!
                      -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full

                      Comment

                      • Spork Schivago
                        Badcaps Legend
                        • Mar 2012
                        • 4734
                        • United States of America

                        #12
                        Re: Insignia NS-37D20SNA14 no power.

                        I think I know why the DCA meter doesn't detect them as bad. With the bad ones, they're resistance is lower than the good ones, but it still blocks electricity the way it's supposed to block it. So, from the DCA's perspective, they measure good. If there weren't four them that were the same part #, I would have never of known they were bad.

                        I think from now on, I'm going to have to find the datasheet for the diodes / general purpose plastic rectifiers, and then use the DMM to verify that they're good.

                        I'm going to search the forums and see if I can find a thread where someone resoldered the LEDs on the LED strips, just to get an idea of what's involved and how to proceed on tearing the screen apart, without damaging it.

                        Thanks!
                        -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full

                        Comment

                        Related Topics

                        Collapse

                        • asr
                          Finding replacement diode iPad Pro 3rd gen A1701
                          by asr
                          Hello, I am looking for help to replace a damaged diode. The tristar was replaced and a diode was damaged in the process. I have a picture of the diode but dont have an exact donor. I mostly have macbooks for donors and only a few ipad and iphone boards. Diode part number: DSF01S30SCAP
                          Im not sure where to find the ipad board number. Anybody have an idea where else this diode is used on other boards? Thanks....
                          07-09-2024, 06:24 PM
                        • unimatrix93
                          TV backlight zener diode
                          by unimatrix93
                          Hello everyone, I'm repairing an LG TV backlight and I noticed some strange behavior when I touching the backlight strip with a missing Zener diode.

                          So I replaced the leds on the strips and they seemingly working fine, but soon as I touch the strip which has a missing Zener diode the whole backlight turns off for a few seconds and then turns back on.

                          Is this caused by the missing diode? If so what kind of zener diode should I use to replace it?.
                          ​​​​
                          The led strips has 9 6V leds.


                          ​​​
                          02-10-2025, 12:13 PM
                        • NicRac
                          monowheel repair,Is the diode the problem?
                          by NicRac
                          Hello everybody☺️ I am glad to be here and looking forward to a good discussion.

                          First of all, I am new here. Therefore I will shortly introduce myself.
                          I am Nico and currently I study Physics.
                          In my freetime I like to build and repair stuff. Especially big battery's.

                          A few years ago I got myself an electric unicycle, monowheel or however you call that.
                          The battery bms was broken so I replaced and resolder that. Nothing big.
                          I used this thing for some years and had a lot of fun. Unfortunately I used it last time in heavy rain. Usually everything...
                          07-26-2024, 06:13 AM
                        • dennis_elx33
                          NO BODY MARKING Diode
                          by dennis_elx33
                          Hello Everyone,
                          I have 1 diode on a circuit that I suspected to be faulty because the forward and reverse bias has a voltage drop reading.
                          While compared to the reading of another diode from the next channel it won't read at reverse bias.
                          Now the problem is; it does not have any body marking.
                          So I tried to sketch the diagram and found out that it is connected to the base and collector of the C3632 transistor.
                          What do you think is this diode?
                          Can you please suggest what part number can i use to replace this faulty diode instead?

                          Hoping that you...
                          06-14-2024, 12:36 AM
                        • eccerr0r
                          Electric lawnmower...purpose of diode...
                          by eccerr0r
                          I was looking at an old battery powered electric lawnmower I picked up as the previous owner didn't want to buy a new board to replace a ruined old board. Tried to study how it was designed - it appears it has a huge 80A contactor...or rather, a 80A relay. It appears to be SPDT to control the motor. A 30A relay protects the circuitry.

                          The weird thing I don't quite get is how this thing is connected. The common contact is connected to the motor. The NO contact is connected to the battery, which is expected, so when the relay is activated, the common is connected to the NO contact and...
                          08-27-2022, 12:54 PM
                        • Loading...
                        • No more items.
                        Working...