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Need help Bypassing a Circuit board in a Powered Sub

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  • Need help Bypassing a Circuit board in a Powered Sub

    Hey All,
    I'm trying to mark projects off of my long list during this stay at home order as I am sure many of you are, I have a question that I'm hoping one or many of you can assist with.....
    I have a pair of Infinity Prelude MTS subs that are near and dear to my heart and would love to use them in a theater setup at my new home, unfortunately many years back they were installed in my basement at a previous house and the basement flooded (this caused the Input board that is in the rear foot of each sub to get wet). If you are not familiar with these subs they are setup different than most Powered subs where as there is a input section low on rear foot of the Sub and the power and amplifier section is on the front face of the sub (never got wet or affected by the water) what I am hoping to accomplish here is finding a way to bypass the original input board and just wire in a signal level (RCA) connection and/or a wireless sub receiver as I have no need for the features offered by the original input board ( i.e speaker level in/ signal level in auto switching, crossover, etc.....)
    Attached is the Infinity Service manual that shows all parts as well as the schematic, Please and Thank you ahead of time
    Attached Files

  • #2
    Is there any way that you can post the required page of the manual as a picture here on PE? (Upload attachments under the text block)

    No offense, but you are pretty new here and I'm leery of downloading and opening a potentially dangerous file from an unknown person. We have bots here occasionally, some of which look fairly legit... we've spent time and energy formulating answers to questions when a bot was proven to be posting such question.

    Sorry for the overly cautious attitude.

    TomZ
    *Veneering curves, seams, using heat-lock iron on method *Trimming veneer & tips *Curved Sides glue-up video
    *Part 2 *Gluing multiple curved laminations of HDF *Cello's Speaker Project Page

    *Building the "Micro-B 2.1 Plate Amplifier -- Part 1 * Part 2 * Part 3 * Part 4 * * Part 5 'Review' * -- Assembly Instructions PDF

    Comment


    • #3
      Originally posted by tomzarbo View Post
      Is there any way that you can post the required page of the manual as a picture here on PE? (Upload attachments under the text block)

      No offense, but you are pretty new here and I'm leery of downloading and opening a potentially dangerous file from an unknown person. We have bots here occasionally, some of which look fairly legit... we've spent time and energy formulating answers to questions when a bot was proven to be posting such question.

      Sorry for the overly cautious attitude.

      TomZ
      Tom,

      I understand your reluctance perfectly, and it is good to be cautious on unknown URLS.
      I work in this area daily, and often run an analysis on URLS via Virustotal.
      They will run the page through 60 or so AV engines. If it comes out clean, you can usually
      trust that the link is not malicious.

      https://www.virustotal.com/gui/home


      I think I hear a difference - wow, it's amazing!" Ethan Winer: audio myths
      "As God is my witness I'll never be without a good pair of speakers!" Scarlett O'Hara

      High value, high quality RS150/TB28-537SH bookshelf - TARGAS NLA!
      SB13/Vifa BC25SC06 MTM DCR Galeons-SB13-MTM
      My Voxel min sub Yet-another-Voxel-build

      Tangband W6-sub

      Comment


      • #4
        Originally posted by donradick View Post

        Tom,

        I understand your reluctance perfectly, and it is good to be cautious on unknown URLS.
        I work in this area daily, and often run an analysis on URLS via Virustotal.
        They will run the page through 60 or so AV engines. If it comes out clean, you can usually
        trust that the link is not malicious.

        https://www.virustotal.com/gui/home
        Good to know Don, thanks for the insight.

        I hate to seem so untrusting... It's just that besides the low post count... the people doing bad things online are always one step ahead of the people doing good things.

        Would that be a site to pass something suspect through before opening it? I'll bookmark that one if so.

        Back to the original post... Would won't necessarily kill a circuit board if it wasn't on shorting stuff out. OP never mentions if it worked or not, just that it got wet.
        I would take it apart and visually inspect. If all looks well, fire a little contact or pot cleaner where necessary, let it dry, and fire it up. Might be just fine.

        TomZ
        *Veneering curves, seams, using heat-lock iron on method *Trimming veneer & tips *Curved Sides glue-up video
        *Part 2 *Gluing multiple curved laminations of HDF *Cello's Speaker Project Page

        *Building the "Micro-B 2.1 Plate Amplifier -- Part 1 * Part 2 * Part 3 * Part 4 * * Part 5 'Review' * -- Assembly Instructions PDF

        Comment


        • #5
          The attachment is fine--just a pdf file that you can find online at other sources. It rated a 0 out of 60 on the page that Don linked to, so it's safe.

          Yes, water isn't a problem for a lot of electronics. In fact, one of the places I worked at many many years ago used water-based solder flux and the final step was to wash it in a conventional dishwasher that they had set up in the production area. However, mechanical stuff like pots and hardware might be corroded and rusted beyond the point of restoration. And lots of water for a long time can cause problems...

          The amp is a fairly powerful BASH design--1000W according to the manual. The input is clearly labeled on page 31 of the pdf file--it is PREAMP. However, there is a FET transistor (Q301) that mutes the signal under certain conditions. It looks like you could remove the LED/MUTE wire to turn off Q301 to defeat the muting, but then there might be a lot of noise during power-up that could be a problem. From a quick look I couldn't find where LED/MUTE is generated, but it doesn't appear to be from the input board.

          Free Passive Speaker Designer Lite (PSD-Lite) -- http://www.audiodevelopers.com/Softw...Lite/setup.exe

          Comment


          • #6
            Yes Tom, definitely bookmark that site for suspect URLS. I use it every day. Pretty reliable.

            I think I hear a difference - wow, it's amazing!" Ethan Winer: audio myths
            "As God is my witness I'll never be without a good pair of speakers!" Scarlett O'Hara

            High value, high quality RS150/TB28-537SH bookshelf - TARGAS NLA!
            SB13/Vifa BC25SC06 MTM DCR Galeons-SB13-MTM
            My Voxel min sub Yet-another-Voxel-build

            Tangband W6-sub

            Comment


            • #7
              Hey guys,
              Thanks for the responses!
              I should have said something like "first time poster long time lurker" or found some way to make it seem less like I was a phishing robot!

              Ok so, yes the input board it trashed (pics attached)

              here are the photos of the amp board and the power supply as well. I was hoping that i would just be able to use the "cables" (J105 and J104) coming from the input board somehow but I'm guessing that's not
              possible?

              Page 29 shows the two cables ( in segment C2) the one labeled "to feature" seems to have a callout for input.... I tried hooking a signal level signal to it and the ground pid with no luck. maybe its muted somehow? would that mute be derived from the input board somehow? if so how would i defeat it?

              Also should i connect the like pins in the "to feature" harness and the "to aux Power" harness? i.e +15v_Aux to +15v etc.




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              Comment


              • #8
                Originally posted by neildavis View Post
                ...

                Yes, water isn't a problem for a lot of electronics. In fact, one of the places I worked at many many years ago used water-based solder flux and the final step was to wash it in a conventional dishwasher that they had set up in the production area. However, mechanical stuff like pots and hardware might be corroded and rusted beyond the point of restoration. And lots of water for a long time can cause problems...
                Neil has a point. Have you tried the subs?

                Comment


                • #9
                  Originally posted by Millstonemike View Post

                  Neil has a point. Have you tried the subs?
                  sure have, and sadly its a no go. you can see how bad the input board is in the first two pics in the above post.

                  Comment


                  • #10
                    Originally posted by neildavis View Post
                    The attachment is fine--just a pdf file that you can find online at other sources. It rated a 0 out of 60 on the page that Don linked to, so it's safe.

                    Yes, water isn't a problem for a lot of electronics. In fact, one of the places I worked at many many years ago used water-based solder flux and the final step was to wash it in a conventional dishwasher that they had set up in the production area. However, mechanical stuff like pots and hardware might be corroded and rusted beyond the point of restoration. And lots of water for a long time can cause problems...

                    The amp is a fairly powerful BASH design--1000W according to the manual. The input is clearly labeled on page 31 of the pdf file--it is PREAMP. However, there is a FET transistor (Q301) that mutes the signal under certain conditions. It looks like you could remove the LED/MUTE wire to turn off Q301 to defeat the muting, but then there might be a lot of noise during power-up that could be a problem. From a quick look I couldn't find where LED/MUTE is generated, but it doesn't appear to be from the input board.
                    bump

                    Comment

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