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Lepai T2020A+ Repair/Upgrade

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  • #61
    Re: Lepai T2020A+ Repair/Upgrade

    Looks like you got lucky, but electrolyte can be conductive. I didn't study the whole thread but when replacing blown caps you need to make sure the board is completely clean. There can be a leftover residue that's partially conductive and is a complete pain to get cleaned.
    "I have not failed. I've just found 10,000 ways that won't work." Thomas A. Edison

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    • #62
      Re: Lepai T2020A+ Repair/Upgrade

      Originally posted by Leroy R View Post
      Well I have 15 of these now and so far they all work, but once you have written up your final summary and parts list maybe I'll give one a try.
      Do you have any testing equipment to see if there is a measurable difference?

      Originally posted by AJ View Post
      Looks like you got lucky, but electrolyte can be conductive. I didn't study the whole thread but when replacing blown caps you need to make sure the board is completely clean. There can be a leftover residue that's partially conductive and is a complete pain to get cleaned.
      I guess I did get lucky. I turned it off the moment I smelled something fishy, so I'm not sure how much of it actually got out. I will go over it with some paint thinner or alcohol before I put it back together.
      Modding the Lepai T-Amp

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      • #63
        Re: Lepai T2020A+ Repair/Upgrade

        I don't have any test equipment here. When I sold my house here in Texas, I shipped everything up to my house in Michigan. I knew it was going to be hard to find work up there, but wasn't expecting it to take this long. I'm gradually starting to bring stuff back down when I go up there. Next trip up there is in July. Planning on bringing my computer that has Sound Easy loaded on it back with me, as well as the test mics and such to go with it.

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        • #64
          Re: Lepai T2020A+ Repair/Upgrade

          http://techtalk.parts-express.com/sh...d.php?t=224481

          look at this thread for a better power supply

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          • #65
            Re: Lepai T2020A+ Repair/Upgrade

            Based on your parts list in Post 39, am I correct in assuming you bought enough parts to modify of these amps.

            George
            "In order to really enjoy a dog, one doesn't merely try to train him to be semi-human. The point of it is to open oneself to the possibility of becoming partly a dog." - Edward Hoagland

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            • #66
              Re: Lepai T2020A+ Repair/Upgrade

              Has anyone tried a 12V ATX PC power supply? They are quite simple to modify for use outside of the computer, put out high amperage and are easily found for free or cheap. I have used one with the Sure 2x25w board with good success. Wire colors are: black= ground, yellow= 12V+, red= 5V+, orange= 3.3V+, green is the switch wire. To turn on the 12V power, connect the green wire to a black. The only other thing needed is a live load on the 12V circuit for function of the regulator circuit. You can use a 12V lightbulb or a 20ohm 10watt resistor between yellow and ground. Cut off and insulate the unused leads and you're in business.

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              • #67
                Re: Lepai T2020A+ Repair/Upgrade

                Originally posted by philiparcario View Post
                http://techtalk.parts-express.com/sh...d.php?t=224481

                look at this thread for a better power supply
                $24 per? Even $15 per with an offer? No thanks man. Please read this thread through and through and you'll see that I already ordered 3 12V 6A power adapters at the rate of $10.25 each shipped, and provided the link to boot! See my quote below:

                http://cgi.ebay.com/ws/eBayISAPI.dll...=STRK:MEWNX:IT

                We'll see now how well it works and if it makes any difference at all.[/QUOTE]

                In addition, I really would have a hard time paying $15 for an amp that cost me $20. It just doesn't make sense.

                Originally posted by moosespeaker View Post
                Based on your parts list in Post 39, am I correct in assuming you bought enough parts to modify of these amps.

                George
                I bought enough parts to modify 3 of these. Like I said, I will be posting a writeup when I have the time, with pictures and explanations, and a full parts list.

                Originally posted by Dirttracker73 View Post
                Has anyone tried a 12V ATX PC power supply? They are quite simple to modify for use outside of the computer, put out high amperage and are easily found for free or cheap. I have used one with the Sure 2x25w board with good success. Wire colors are: black= ground, yellow= 12V+, red= 5V+, orange= 3.3V+, green is the switch wire. To turn on the 12V power, connect the green wire to a black. The only other thing needed is a live load on the 12V circuit for function of the regulator circuit. You can use a 12V lightbulb or a 20ohm 10watt resistor between yellow and ground. Cut off and insulate the unused leads and you're in business.
                They are large, clunky, ugly, not as portable, and offer outputs I don't need for 3.3V and 5V (contributing to their size). In addition, while I do have plenty of these to spare, they are also more expensive for those who don't have them. $10.25 for the adapters I bought is really quite competitive.
                Modding the Lepai T-Amp

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                • #68
                  Re: Lepai T2020A+ Repair/Upgrade

                  Originally posted by XtremeRevolution View Post
                  Input cap
                  1 x 16v 3300uf

                  Other/Output electrolytic caps
                  2 x 16v 100uf
                  1 x 16v 470uf
                  2 x 16v 220uf
                  2 x 50v 1uf
                  2 x 50v 1.7uf - cannot find a replacement.

                  Other/Output film caps
                  1x 63v .1uf - 104j
                  6x 63v .47uf - 474z
                  I've updated the voltage for the output film cap above. I've modified 3 of these amps now and have had significant gains in sound quality with all three. Compared to the modified amps, the stock ones sound like they're being played in a bathroom. Yeah, its that big of a difference.

                  I have plenty of pictures taken, so I'll be making a writeup soon. I apologize for the delay.

                  Here's an updated parts list. I have substituted the 5600uf capacitor as it is the exact same size as the 4700uf and works perfectly. I have removed the 2.2uf capacitor that was meant to replace the 1.7uf capacitor because it doesn't work. The 1.7uf cap must be replaced with another 1.7uf cap. When I attempted to use the 2.2uf cap, I introduced a whole slew of distortion, so I put the stock ones back in. The inductors will not be touched.



                  1x Polypropylene Film Capacitors 0.10uF 450VDC 5% (to replace the red one to the right of the Tripath chip)
                  https://www.mouser.com/Search/Produc...-ECW-F2W104JAQ


                  6x Polypropylene Film Capacitors 0.47uF 450VDC 5% (direct replacement for the output caps)
                  https://www.mouser.com/Search/Produc...-ECW-F2W474JAQ


                  1x Aluminum Electrolytic Capacitors - Leaded 16VDC 5600uF (direct replacement for the input cap)
                  https://www.mouser.com/Search/Produc...67-EEU-FR1C562



                  2x Aluminum Electrolytic Capacitors - Leaded 50volts 1uF 20% (direct replacement)
                  https://www.mouser.com/Search/Produc...47-UKW1H010MDD


                  2x Aluminum Electrolytic Capacitors - Leaded 25volts 220uF 20% (direct replacement)
                  https://www.mouser.com/Search/Produc...47-UKW1E221MPD


                  1x Aluminum Electrolytic Capacitors - Leaded 16volts 470uF 20% (direct replacement)
                  https://www.mouser.com/Search/Produc...47-UKW1C471MPD


                  2x Aluminum Electrolytic Capacitors - Leaded 16volts 100uF 20% (direct replacement)
                  https://www.mouser.com/Search/Produc...47-UKW1C101MDD
                  Modding the Lepai T-Amp

                  Comment


                  • #69
                    Re: Lepai T2020A+ Repair/Upgrade

                    I like your choice of up graded caps. Did you also experiment with ferrite beads from out put to speaker connector?
                    i will be looking forward to your write up.

                    Comment


                    • #70
                      Re: Lepai T2020A+ Repair/Upgrade

                      I like your choice of upgraded caps. Did you also experiment with ferrite beads from out put to speaker connector?
                      i will be looking forward to your write up.

                      Comment


                      • #71
                        Re: Lepai T2020A+ Repair/Upgrade

                        Originally posted by Pete00t View Post
                        I like your choice of up graded caps. Did you also experiment with ferrite beads from out put to speaker connector?
                        i will be looking forward to your write up.
                        I did not experiment with any ferrite beads. If you do, please let me know how it goes.
                        Modding the Lepai T-Amp

                        Comment


                        • #72
                          Re: Lepai T2020A+ Repair/Upgrade

                          Originally posted by XtremeRevolution View Post

                          I have plenty of pictures taken, so I'll be making a writeup soon. I apologize for the delay.
                          first thanks so much for detailed parts list, being rather a newbie, I am anxiously waiting for pictures of which part need to be replaced by which.

                          Listed parts with exact website is VERY useful for people like me.

                          will be waiting.

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                          • #73
                            Re: Lepai T2020A+ Repair/Upgrade

                            The writeup is done.

                            http://techtalk.parts-express.com/sh...26#post1756126
                            Modding the Lepai T-Amp

                            Comment


                            • #74
                              Re: Lepai T2020A+ Repair/Upgrade

                              Hello All;

                              I have been an active audio repair/restoration hobbyist for about 5 years now. This is my first time running across this board.

                              I found this thread because I just received my Lepai TA2020 A+ in the mail from PartsExpress and wanted to see what kind of mods everyone is working on.

                              I plan to recap the unit tonight.

                              One thing has me perplexed, however - the 1.75uF caps in the tone control circuit. If they are indeed 20% tolerance, than a 2.2uF cap would be at the top end of that tolerance and would most likely be acceptable depending on the actual tolerance of the 2.2uF replacement caps.

                              Have you counted out that the 2.2uF replacement caps you used were bad or polarized? I can do some digging on my own but wanted to toss out that idea just in case.

                              1.7uF is an uncommon value in tone control circuits (at least the discrete SS ones of the 70's and 80's) so it's a bummer when you run across them!

                              Great thread, though, I look forward to hearing this little guy. I plan to use him to replace the Kenwood 700C / 700M combo I use at the office. Overkill.

                              Rob

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                              • #75
                                Re: Lepai T2020A+ Repair/Upgrade

                                You can find a Tantalum in 1.7ufd.
                                "Not a Speaker Designer - Not even on the Internet"
                                “Pride is your greatest enemy, humility is your greatest friend.”
                                "If the freedom of speech is taken away, then dumb and silent we may be led, like sheep to the slaughter."

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