Akai LCT2662 with bad caps

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  • aliasdck
    Senior Member
    • Sep 2009
    • 100

    #1

    Akai LCT2662 with bad caps

    I received this TV for free from a friend. He had already opened it and gave it to me in pieces. Not sure what symptoms the TV suffers from but I suspect it doesn't even turn on.

    Lots of bulging/spooging caps on the power supply. Here is a list of the caps:

    (8) 2200 uF 25V
    (4) 3300 uF 35V
    (7) 1000 uF 10V
    (1) 1000 uF 6.3V
    (4) 100 uF 25V

    The three big caps in the center are marked like this (going to replace them as well):

    (1) ZS 47uF 450WV
    (2) LX 100uF 450WV

    All caps are temp rated at 105 and are KSD Brand. I plan to recap all of them, just thought I'd post here and see if anyone has any thoughts/opinions. For example, should I consider increasing the voltage rating on a few of these caps, or would simply replacing them with good quality caps of the same rating suffice. Anything else I should consider?
    Attached Files
    Last edited by aliasdck; 09-30-2009, 08:09 PM.
  • Toasty
    Badcaps Legend
    • Jul 2007
    • 4171

    #2
    Re: Akai LCT2662 with bad caps

    Increasing the voltage rating doesn't buy you anything. They're not failed from overvoltage, just crap caps.

    >>The three big caps in the center are marked like this (going to replace them as well):<<

    Good! Somebody's paying attention.

    >>or would simply replacing them with good quality caps of the same rating suffice.<<
    Yes.

    Check the connections on all the transformers. Common to have bad joints there.

    Toast
    veritas odium parit

    Comment

    • aliasdck
      Senior Member
      • Sep 2009
      • 100

      #3
      Re: Akai LCT2662 with bad caps

      Thanks for the advice toasty.

      The reason why I asked if I should consider increasing the voltage rating of a few of the caps is because I had come across somebody suggesting it elsewhere on the internet for this particular power supply - however, I'm fairly confident whoever designed this board would have used the correct voltage rating and that the problem was crappy quality caps were used... just thought I'd get a second opinion.

      I'm definetly going to be doing some resoldering as I can see a few suspect solder joints as you mentioned.

      Again, thanks for the pointers.

      I'll report back in a few days with the results.

      Comment

      • kc8adu
        Super Moderator
        • Nov 2003
        • 8832
        • U.S.A!

        #4
        Re: Akai LCT2662 with bad caps

        i rebuilt a similar unit a while back.used panasonic fm for most.the originals had puked all over the shield and even through the vents in the back cover.
        this will be a test of the fm's as this unit is in a sports bar and rarely turned off.

        Comment

        • Krankshaft
          Badcaps Legend
          • Jan 2007
          • 2328
          • USA

          #5
          Re: Akai LCT2662 with bad caps

          Man I haven't seen so many hatched caps so close to each other it looks like Alien in there .

          Are there any caps in there not getting baked by a transformer or heatsink?
          Last edited by Krankshaft; 10-02-2009, 08:22 AM.
          Elements of the past and the future combining to make something not quite as good as either.

          Comment

          • aliasdck
            Senior Member
            • Sep 2009
            • 100

            #6
            Re: Akai LCT2662 with bad caps

            It's the worst I've seen as well.

            I've got all the caps picked out except for the three big ones.

            On the three caps what does the W indicate? For example, the one marked 47uF 450WV? I'm assuming I just need to pick out a 47uF 450V cap. Any suggestions on what type of cap? The rest I've getting panasonic fc or fm types.

            Comment

            • Toasty
              Badcaps Legend
              • Jul 2007
              • 4171

              #7
              Re: Akai LCT2662 with bad caps

              WV = Working Volts/Voltage

              Nippon Chemi-Con SMM
              UCC - KMG
              Panasonic EB
              CDE - SLP

              Choose what fits and has a lower ESR and higher ripple current rating than the others. I can't locate a datasheet for the KSD caps and the referenced website is not showing any component parts. It a SWAG* on those caps.

              Toast
              .
              .
              .
              .

              * Scientific Wild Ass Guess
              veritas odium parit

              Comment

              • aliasdck
                Senior Member
                • Sep 2009
                • 100

                #8
                Re: Akai LCT2662 with bad caps

                Thanks. I'll check those out.

                For the 100uF 450V caps I am having trouble finding caps in a physical size that will work (most are too tall). There are a few that I have found that are the right rating and size but they are snap-in style. From the picture, it looks like the legs might be long enough to be inserted and soldered to the board. The leg spacing spec fits what I need. Will these fit/solder in fine or should I keep looking?

                Comment

                • Toasty
                  Badcaps Legend
                  • Jul 2007
                  • 4171

                  #9
                  Re: Akai LCT2662 with bad caps

                  Those big caps are usually the snap-in variety. The leaded ones are typically seen laying on their side.

                  Snap-in means the legs are flattened (wider) and bent in a way that when they are set into the board, they stay upright and in place. They "snap-in". It makes them capable of being wave-soldered. The manufacturer doesn't have to glue them in place or have them manually soldered.

                  Toast
                  veritas odium parit

                  Comment

                  • aliasdck
                    Senior Member
                    • Sep 2009
                    • 100

                    #10
                    Re: Akai LCT2662 with bad caps

                    AH! That makes sense. I was thinking they snapped into some sort of base. Learning as I go.

                    Parts are on order and I'll update once I get the TV recapped.

                    Thanks.

                    Comment

                    • PCBONEZ
                      Grumpy Old Fart
                      • Aug 2005
                      • 10661
                      • USA

                      #11
                      Re: Akai LCT2662 with bad caps

                      I just finished recapping a LCT2785TA.
                      The caps you need will depend on the specs of the original caps.
                      - But since I dunno where to get KSD data sheets.
                      Panasonic FM should be as good or better than anything in there if you can source FM replacements in the right diameters.
                      If you can't get them in FM then fail-up to something like:
                      Rubycon MBZ/MCZ, Panasonic FJ/FL, Sanyo WG
                      -
                      Mine also had some 8-12.5 mm caps on the video board.
                      Should replace those preemptively while you have it apart.
                      Also anything with a vent that isn't temperature rated for 105c.
                      Panasonic FC or Nichicon PW should be good enough for small [less than 8mm] caps on the video board or tuners.
                      For 8mm and up, fail safe to FM or better.
                      .
                      Mann-Made Global Warming.
                      - We should be more concerned about the Intellectual Climate.

                      -
                      Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind.

                      - Dr Seuss
                      -
                      You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
                      -

                      Comment

                      • PCBONEZ
                        Grumpy Old Fart
                        • Aug 2005
                        • 10661
                        • USA

                        #12
                        Re: Akai LCT2662 with bad caps

                        Originally posted by aliasdck
                        AH! That makes sense. I was thinking they snapped into some sort of base. Learning as I go.

                        Parts are on order and I'll update once I get the TV recapped.

                        Thanks.
                        Not quite. - No base.
                        Snap-in means the leads are bent so they 'snap into' the holes in the PCB.
                        It keeps them from falling out when you turn the board over to solder them in.
                        Mann-Made Global Warming.
                        - We should be more concerned about the Intellectual Climate.

                        -
                        Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind.

                        - Dr Seuss
                        -
                        You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
                        -

                        Comment

                        • Toasty
                          Badcaps Legend
                          • Jul 2007
                          • 4171

                          #13
                          Re: Akai LCT2662 with bad caps

                          Where have I heard this before....



                          Look up ^ ^ ^ a few posts.... OLD MAN.
                          veritas odium parit

                          Comment

                          • PCBONEZ
                            Grumpy Old Fart
                            • Aug 2005
                            • 10661
                            • USA

                            #14
                            Re: Akai LCT2662 with bad caps

                            Originally posted by Toasty
                            Where have I heard this before....
                            Just before he thought there was a base.
                            Mann-Made Global Warming.
                            - We should be more concerned about the Intellectual Climate.

                            -
                            Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind.

                            - Dr Seuss
                            -
                            You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
                            -

                            Comment

                            • PCBONEZ
                              Grumpy Old Fart
                              • Aug 2005
                              • 10661
                              • USA

                              #15
                              Re: Akai LCT2662 with bad caps

                              The KSD labeled caps are made by P & B Co., Ltd. [China].
                              http://www.pb.com.cn/english.htm
                              http://www.pb.com.cn/en/cp1/aluminium.htm

                              You seem to have the KM Series:
                              KM Data Sheet -> http://www.pb.com.cn/en/cp1/p11.htm

                              .
                              Mann-Made Global Warming.
                              - We should be more concerned about the Intellectual Climate.

                              -
                              Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind.

                              - Dr Seuss
                              -
                              You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
                              -

                              Comment

                              • PCBONEZ
                                Grumpy Old Fart
                                • Aug 2005
                                • 10661
                                • USA

                                #16
                                Re: Akai LCT2662 with bad caps

                                Like most crap brands they don't list all their caps.
                                GL is supposedly their best Series.

                                Spot checking Ripple/ESR for both KM and GL shows all you need to upgrade those is Panasonic FC or Nichicon PW. [And it's a substantial upgrade. The PM aren't even low ESR caps.]

                                ~~~~

                                You didn't say -how long- is -too long- but here are some to look at.

                                100uF 450v - 18 mm Dia. x 35.5 mm
                                http://www.mouser.com/ProductDetail/...l%252blA%3d%3d

                                100uF 450v - 18 mm Dia. x 40 mm
                                http://www.mouser.com/ProductDetail/...RgzBcERn8iw%3d

                                100uF 450v - 18 mm Dia. x 40 mm
                                http://www.mouser.com/ProductDetail/...48zpGHB045Y%3d

                                100uF 450v - 22 mm Dia. x 30 mm
                                http://search.digikey.com/scripts/Dk...name=P11799-ND

                                100uF 450v - 22 mm Dia. x 30 mm
                                http://search.digikey.com/scripts/Dk...me=565-3016-ND

                                100uF 450v - 22 mm Dia. x 30 mm
                                http://search.digikey.com/scripts/Dk...name=P14100-ND

                                .
                                Mann-Made Global Warming.
                                - We should be more concerned about the Intellectual Climate.

                                -
                                Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind.

                                - Dr Seuss
                                -
                                You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
                                -

                                Comment

                                • aliasdck
                                  Senior Member
                                  • Sep 2009
                                  • 100

                                  #17
                                  Re: Akai LCT2662 with bad caps

                                  Forgot to mention the physical size, sorry about that.

                                  Original caps are 18mm Dia x 35mm x 7.5mm

                                  Could go as big as 18mm by 40mm... don't really have much room for a larger diameter (maybe 20mm) but I don't think it matters anyways as I think most of the caps I've seen larger than 18mm have 10mm lead spacing.

                                  Any of the three PCBONEZ mentioned would work but they are not currently in stock.

                                  I definetly need to replace these 3 large caps... I've desoldered them and checked them with a capacitance meter and they are AFU.

                                  How about this one?

                                  http://www.mouser.com/ProductDetail/...RgzBcERn8iw%3d

                                  Comment

                                  • PCBONEZ
                                    Grumpy Old Fart
                                    • Aug 2005
                                    • 10661
                                    • USA

                                    #18
                                    Re: Akai LCT2662 with bad caps

                                    Second on list is still in stock as of now.
                                    They were all in stock when I posted.
                                    Mann-Made Global Warming.
                                    - We should be more concerned about the Intellectual Climate.

                                    -
                                    Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind.

                                    - Dr Seuss
                                    -
                                    You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
                                    -

                                    Comment

                                    • PCBONEZ
                                      Grumpy Old Fart
                                      • Aug 2005
                                      • 10661
                                      • USA

                                      #19
                                      Re: Akai LCT2662 with bad caps

                                      Yes that one.
                                      Mann-Made Global Warming.
                                      - We should be more concerned about the Intellectual Climate.

                                      -
                                      Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind.

                                      - Dr Seuss
                                      -
                                      You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
                                      -

                                      Comment

                                      • aliasdck
                                        Senior Member
                                        • Sep 2009
                                        • 100

                                        #20
                                        Re: Akai LCT2662 with bad caps

                                        Okay.

                                        I received all my replacement caps yesterday and installed them today. I also did some resoldering around the board as well.

                                        I put everything back together and plugged it in. I turned on the main switch and right away the power led turned on (red - standbye I assume) for a split second and then turned off... then about five seconds later it turns back on (red) and stays on. Right around the time it turns off I can hear a slight squealing/screeching sound for a second or two.

                                        (side note - I used to work on large UPS and rectifieries several years ago. I've heard this screeching sound before whenever there was a shorted semiconductor device - such as a large scr - and a hellacious amount of current would pass through it. This squealing/screeching sound sounded very familar but much quieter... it could just be the power supply/tv powering up for all I know, but I thought I'd mention it as is this is my first large TV repair so I'm not too familiar with them)

                                        After the red led turns back on, I tried hitting the power/standbye button but the TV would not respond.

                                        I flipped it over and checked power supply voltages. Everything checks out ok... 3.3v , 5v and 15v (marked 11 - 16v).

                                        I checked the connections from the buttons into the main pcb. Each line (Power on, vol + -, Chan + -, etc) reads roughly 1.8V to ground and then change to .4V when pressed... so when I am pushing the power on button, the signal is getting to the main pcb, but nothing is happening.

                                        So what I'm thinking is either there is a problem with the main pcb as well OR there is still a problem with the power supply and what I'm seeing/hearing just after I turn on the main switch is indicating this. It seems odd to me that the main power led would shut off for a few seconds as it does.

                                        What I don't know is how this TV normally starts up. When I turn on the main switch, should it automatically power on and turn on or is it waiting for me to also hit the power on switch as well.

                                        Perhaps during the initial power up something is occuring (such as the backlight's/display trying to turn on) that is pulling the power supply down. I'll have to monitor power supply voltages just after powering it up to see, but I didn't have time today to do so.

                                        Also, once I get passed the five seconds where the power led is off and it comes back on steady, there is a small indicator surfaced mount led on the main pcb labelled led 1 (or something similar) that is blinking steadily...

                                        I only get a few minutes each day at work to play around with this set, so I don't have much time for troubleshooting and wont get back to see it until monday, but I was hoping somebody had a little insight for me. If its a problem with the main PCB, I will likely have to scrap this project... I think I may be in over my head in terms of my own troubleshooting skills/equipment and I cant afford to replace the pcb if that is the problem.

                                        Any advice is appreciated.

                                        Comment

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