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Re: Ensemble RXTX - no RF from SI570

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  • pauldebono@rocketmail.com
    Alan, Good day I have found the culprit. I was getting different voltages for different ground points on pin 6 of the SI570, 3.3v on one ground point , and
    Message 1 of 4 , Nov 4, 2012
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      Alan,

      Good day

      I have found the culprit.

      I was getting different voltages for different ground points on pin 6 of the SI570, 3.3v on one ground point , and 0.95 volts on others. I did not get complete continuity at variuos gound points- pin 4 on J1 pin 2 on U2 and pin 3 on u3

      Another touch with the soldering iron, cleared the problem

      Thanks for your help

      Paul
      9H1FQ

      --- In softrock40@yahoogroups.com, Malti <pawlud@...> wrote:
      >
      > Alan,
      > Thanks.
      >
      > Must say, I hurried a bit to see the rf coming out !
      > As, my test equipment is in another room, I made a quick test, by inputting
      > a 26 Mhz signal to get into the fm broadcast band (x4), and this failed.
      >
      > I have noticed that the voltage on pin 1 of the opto toggles between 1.7
      > and 0 volts when clicking PTT on screen.
      >
      > So, I will be doing a proper test with my frequency meter & scope, later
      > today.
      > Voltages on all psu chips are correct, so are the parameters on the CFGSR
      >
      > The SI570 has been soldered with the thinnest solder around. Never had any
      > blobs, shorts, and excessive solder etc. I must have soldered five of them
      > on other projects, and they never failed, right from the first time.
      >
      > Paul
      >
      >
      > On 4 November 2012 07:28, Alan <alan4alan@...> wrote:
      >
      > > **
      > >
      > >
      > >
      > > ----- Original Message -----
      > > Subject: [softrock40] Ensemble RXTX - no RF from SI570
      > >
      > > Have you measured the voltages on the pins of the Si570?
      > > Does the CFGSR "Test" tab show all values with no error message when you
      > > click "Get"?
      > >
      > > With no U1 fitted the Si570 should output 56.32MHz, can you test for that
      > > at C76? How do you test?
      > >
      > > This frequency should be present. It does not need any data to start it.
      > > It needs a good scope to see the sharp control pulses but this will not be
      > > your problem.
      > >
      > > A quick search of this group's messages brings this (and others) <
      > > http://groups.yahoo.com/group/softrock40/message/52768> the actual
      > > batch referred was even earlier.
      > >
      > > 73 Alan G4ZFQ
      > >
      > > >I am building the Ensemble RXTX, and has just finished the Local
      > > oscillator section. The power supplies are good.
      > > >
      > > > The software is responding ok.
      > > > ABPF filter off
      > > > P1/PTT is responding on screen, to PTT button (repeat ticked)
      > > > The Test VFO frequency tuning on screen , varies at x4
      > > > But no RF is coming out of the SI570
      > > > I am taking the output from C3. R13 & R14 are not yet installed.
      > > >
      > > > The builders notes say "Measure the outputs at the points indicated as
      > > "LO Out" and "/PTT. I cannot see these points on my
      > > > pcb(version 5/24/10) ! Do I have to activate the PTT circuit, or
      > > something else on the pcb ?
      > > >
      > > > It is not the first time that I had soldered an SI570 and it never
      > > failed !
      > > >
      > > > How can I test if I have controlling signals from ATTiny85 at SDA & SCL
      > > ??
      > > >
      > >
      > >
      > >
      >
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