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Vizio E60-E3 power supply repair

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    Vizio E60-E3 power supply repair

    Hey all,

    I have a Vizio E60-E3 power supply board (1p-1156800-1010) that is non-functioning. According to the last owner, it got damaged by a lightning strike or a power brownout.

    I'm pretty new to repairing these sorts of things but I've had some success in the past. This one is throwing me for a huge loop though.

    There's no standby voltage on the board at all. Actually, on the connector there's no voltages at all. Diodes seem intact and weren't shorted or blown, MOSFETs seem intact and testing them as diodes looked okay, but I'm not 100% sure if I've been checking those correctly. No bulging or burst caps, pretty much no sign of trouble.

    I've done a little digging and the hot side of the board seems like it's mostly intact. I get some 170V across the legs of the main capacitor when it's plugged in.

    I kept getting intermittent readings on one of the chips with my meter so I greenwired the trace and it stayed solid. The chip is a TEA18363T or variant thereof as far as I can tell. I get 12.4V on pin 1 of the chip and 15V at pin 5, referenced to the ground on the chip.

    What's really weird is that I get a consistent voltage difference of 170V (DC) across the low-voltage transformer on the hot side. I get a 0V AC reading across the loops but this may make sense if I'm referencing ground wrong.

    On the cold side of that transformer, I get nothing - no voltages anywhere. The coils are intact and read close to 0 ohms across the terminals, so it doesn't seem like the transformer itself got fried. As best as I can figure, there's a voltage potential difference but it's not oscillating therefore I get no power on the other side of the transformer?

    The only other thing I've seen is a SOT-23 transistor was blown on the middle set of traces on the cold side of the board (Q201, the one I believe should be the standby voltage line). There's a few surrounding transistors that all seemed to be 2n7002 models, so I replaced it with one of those - didn't change anything though.

    Pics are attached (I can annotate them if need be) - if anyone has ideas on this I'd love to hear them, this one is really stretching my knowledge. Thanks!
    Attached Files

    #2
    Re: Vizio E60-E3 power supply repair

    With power cord unplugged, unhook cable from powerboard to mainboard, leave it unhooked, plug power cord into powerboard, check those 16 pins of connector, see if you have standby or anything with it like that.

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      #3
      Re: Vizio E60-E3 power supply repair

      Just unplug everything from the powerboard and plug the power cord in, see if you have any voltages, you should at least have standby, if not, then you probably need to fix the standby circuit first.

      Comment


        #4
        Re: Vizio E60-E3 power supply repair

        With the power supply disconnected from the main you should have +16V, if you don't. check the value of R12. Since the HV trace going to U1 I suspect the ic is likely bad.
        Check if the fet Q1 is ok and not shorted.
        If Q201 was blown I suspect someone tried forcing the power supply on the wrong way.

        Comment


          #5
          Re: Vizio E60-E3 power supply repair

          Was a lightning strike or brownout according to first post.

          Comment


            #6
            Re: Vizio E60-E3 power supply repair

            Originally posted by nomoresonys View Post
            Just unplug everything from the powerboard and plug the power cord in, see if you have any voltages, you should at least have standby, if not, then you probably need to fix the standby circuit first.
            To clarify, I tested all the voltages above with the board standalone. It's definitely something to do with the standby circuit.

            Comment


              #7
              Re: Vizio E60-E3 power supply repair

              Originally posted by R_J View Post
              With the power supply disconnected from the main you should have +16V, if you don't. check the value of R12. Since the HV trace going to U1 I suspect the ic is likely bad.
              Check if the fet Q1 is ok and not shorted.
              If Q201 was blown I suspect someone tried forcing the power supply on the wrong way.
              In standalone I don't get any voltages on the connector.

              R12 reads 64.5 kohm.

              Q1 reads ~0.5V activation in a diode check crossing the HV separation cut on the board. Between pins 1 and 3 on it reads a pretty low resistance (beeps on a continuity check) but there's a couple SMT resistors bridging those so that may be normal behavior.

              Both those measurements were in-circuit, I can desolder later tonight when I get home from work if need be. I appear to be the first person working on the board since most of the conformal coating was intact, I don't know what that speaks for Q201.
              Last edited by bambammakerman; 11-18-2019, 02:10 PM.

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                #8
                Re: Vizio E60-E3 power supply repair

                R12 is likely ok, I thought it was a fuseable for the supply for the fet but it's not.
                I suspect the ic could be damaged, if you look at the TEA18363T pdf, pin 5 has a 5V internal zener, you measured 15V on that pin. Vio(AUX) max = +5V
                The circuit is fairly simple, U1 drives the fet and it switches the 160v across T1 primary. This will give you the standby voltage which could be around 8~12v in standby mode. once the power supply gets the PS-ON signal, it will output the full 16 volts.
                What's really weird is that I get a consistent voltage difference of 170V (DC) across the low-voltage transformer on the hot side. I get a 0V AC reading across the loops but this may make sense if I'm referencing ground wrong
                What do you mean here? are you getting 170v ACROSS the primary winding? or do you mean 170v from HOT GROUND to each side of the primary winding?
                Also 0v AC across the loops? what loops?
                Last edited by R_J; 11-18-2019, 05:24 PM.

                Comment


                  #9
                  Re: Vizio E60-E3 power supply repair

                  Originally posted by R_J View Post
                  R12 is likely ok, I thought it was a fuseable for the supply for the fet but it's not.
                  I suspect the ic could be damaged, if you look at the TEA18363T pdf, pin 5 has a 5V internal zener, you measured 15V on that pin. Vio(AUX) max = +5V
                  The circuit is fairly simple, U1 drives the fet and it switches the 160v across T1 primary. This will give you the standby voltage which could be around 8~12v in standby mode. once the power supply gets the PS-ON signal, it will output the full 16 volts.

                  What do you mean here? are you getting 170v ACROSS the primary winding? or do you mean 170v from HOT GROUND to each side of the primary winding?
                  Also 0v AC across the loops? what loops?
                  I apologize for abandoning this thread - life happened, and then continued happening.

                  I replaced the TEA18363T IC and no change in response so far. I think I had counted my pins wrong because double checking everything, all the voltages across that chip seem within range. In reference to the ground on pin 2 of the chip, I get 14V on VCC (pin 1), 60V on pin 8 (HV), and 0V on pin 5 (VAUX).

                  As for the transformer, I'm getting ~170V across the primary winding on the hot side, but nothing seems to be working correctly on the other side.

                  I'm trying to improve my diagnostic skills and my initial thoughts are that either U1 isn't switching and doesn't "activate" somehow so my transformer is dead in the water, the transformer itself is broken, or D201 has failed.

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