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Re: Help with Ensemble RX II

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  • n5gx_dt
    I was successful at removing the chip, thank to some solder wick and a small solder sucker. No physical damage to the chip or board. I m not so sure about
    Message 1 of 11 , Aug 19, 2013
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      I was "successful" at removing the chip, thank to some solder wick and a small solder sucker. No physical damage to the chip or board. I'm not so sure about the innereds of the chip. It certainly did solve the 5 volt problem, but I don't get all the right voltages on the other pins.

      Pin 1 = 5 (OK)
      Pin 2 = 5 (S/B 2.5)
      Pin 3 = 1.7 (S/B 2.5)
      Pin 4 = 5 (OK)
      Pin 5 = 0 (S/B 2.5)
      Pin 6 = 5 (S/B 2.5)
      Pin 7 = 0 (OK)
      Pin 8 = 0 (S/B 2.5)
      Pin 9 = 5 (S/B 2.5)
      Pin 10 = 5 (OK)
      Pin 11 = 1.7 (S/B 2.5)
      Pin 12 = 5 (S/B 2.5)
      Pin 13 = 5 (OK)
      Pin 14 = 5 (OK)

      I have looked closely for solder bridges and see none. My only conclusion now is that in all the proceeding wrong steps, I did the chip harm and need to replace it. Bitter lesson learned about following instructions.

      Dan

      --- In softrock40@yahoogroups.com, "R. R. (Robby) Robson" <rrrobson@...> wrote:
      >
      > At this stage, the best way to remove the chip is with one of those $14
      > Hobby Lobby embossing hot air guns and some aluminum foil cut to expose the
      > chip and protect the other components' soldering
      >
      >
      > On Mon, Aug 19, 2013 at 9:17 AM, n5gx_dt <djtosh@...> wrote:
      >
      > > **
      > >
      > >
      > > Rich:
      > > I think you may have nailed it. I kept looking at those pictures of U06
      > > and didn't follow that explanation of the pin one orientation.
      > >
      > > Thank you so much.
      > >
      > > Now to see if I can remove it. If it parishes, I'll just have to get a new
      > > one.
      > >
      > > Thanks again,
      > > Dan
      > >
      > >
      > > --- In softrock40@yahoogroups.com, "R. R. (Robby) Robson" <rrrobson@>
      > > wrote:
      > > >
      > > > "- U06 us oriented correctly. Banded end to the left. Matched the
      > > photos."
      > > >
      > > > There is a difference between the image in the BOM (showing how to find
      > > pin
      > > > 1 when the chip is oriented so you can read the inscription) and the
      > > > orientation shown in the BOM (showing how the chip is to be oriented).
      > > > U6 must be installed such that the pin 1 aligns with the upper right-hand
      > > > pad when viewing the bottom of the board with the Si570 on the right.
      > > >
      > > > From your comment, it appears that you installed U6 such that pin 1 was
      > > > aligned with the lower left-hand pin.
      > > >
      > > >
      > > > On Mon, Aug 19, 2013 at 8:40 AM, n5gx_dt <djtosh@> wrote:
      > > >
      > > > > **
      > >
      > > > >
      > > > >
      > > > > Thanks for the several responses. here is what I have tried.
      > > > > - U06 us oriented correctly. Banded end to the left. Matched the
      > > photos.
      > > > > - With U06 isolated I measured 5 vdc from the supply across a 2K load.
      > > I
      > > > > even did it across a 1K load and maintains the 5 vdc.
      > > > > - I guess the next thing is to (try to) remove U06 and check under it.
      > > I
      > > > > assume it is possible to remove the chip w/o destroying it or the
      > > board.
      > > > >
      > > > > I just don't understand how, when I measure 20K at pin 1 of U6 that
      > > > > applying the 5 volts to that spot pulls the 5 volts down to .7. I even
      > > > > loaded the 5 volt line with a 500 ohm resistor and the 5 volts holds
      > > > > steady. The chip never feels warm, but that is the only load. Sorry,
      > > I'm
      > > > > just venting now.
      > > > >
      > > > > I'll see if I can get the chip off. I may have to send this thing off
      > > to
      > > > > someone who knows what they are doing.
      > > > >
      > > > > Dan
      > > > >
      > > > >
      > > > > --- In softrock40@yahoogroups.com, "n5gx_dt" <djtosh@> wrote:
      > > > > >
      > > > > > I begun assembling my first Solfrock Radio (Ensemble RX II). I was
      > > doing
      > > > > fine until I hit the AC74 (U06) Divider. When I went to test the
      > > voltages,
      > > > > instead of the 5 volts on 1, 4, 10, 13 & 14 I only have .7 volts. I
      > > spent a
      > > > > few hours (yes hours) checking for solder bridges to no avail. So I
      > > started
      > > > > to worry that my powers supply might be bad, but to be able to check
      > > for
      > > > > the regulated 5 volts I had to isolate the line going to the U06. In
      > > > > desperation I cut the trace and the Power supply is providing a steady
      > > > > 5vdc. As soon as I restore the connection to U06, it drops to .7 volts.
      > > > > With U06 isolated I measure 20K ohms to ground on pins 1, 4, 10, 13 &
      > > 14,
      > > > > so it doesn't appear to be a short there. Could something be fried
      > > inside
      > > > > the AC74 that brings down the 5 volts? I'm at a lose. Any ideas would
      > > be
      > > > > appreciated.
      > > > > >
      > > > > > Dan
      > > > > > N5GX
      > > > > >
      > > > >
      > > > >
      > > > >
      > > >
      > > >
      > > >
      > > > --
      > > > Cheers,
      > > > Robby
      > > >
      > > > Richard R. (Robby) Robson
      > > > LTC USA (RET)
      > > > www.wb5rvz.com
      > > > www.wb5rvz.org
      > > > www.rafino.org
      > > >
      > >
      > >
      > >
      >
      >
      >
      > --
      > Cheers,
      > Robby
      >
      > Richard R. (Robby) Robson
      > LTC USA (RET)
      > www.wb5rvz.com
      > www.wb5rvz.org
      > www.rafino.org
      >
    • Paul
      I prefer Chip Quick, a low temperature solder. Expensive, but works very well. de Paul, W8AEF From: R. R. (Robby) Robson Sent: Monday, August 19, 2013 8:12 AM
      Message 2 of 11 , Aug 19, 2013
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        I prefer Chip Quick, a low temperature solder.
         
        Expensive, but works very well.
         
        de Paul, W8AEF
         
        Sent: Monday, August 19, 2013 8:12 AM
        Subject: Re: [softrock40] Re: Help with Ensemble RX II
         
         

        At this stage, the best way to remove the chip is with one of those $14 Hobby Lobby embossing hot air guns and some aluminum foil cut to expose the chip and protect the other components' soldering


        On Mon, Aug 19, 2013 at 9:17 AM, n5gx_dt <djtosh@...> wrote:
         

        Rich:
        I think you may have nailed it. I kept looking at those pictures of U06 and didn't follow that explanation of the pin one orientation.

        Thank you so much.

        Now to see if I can remove it. If it parishes, I'll just have to get a new one.

        Thanks again,
        Dan



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