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70836Re: RX ensemble II No output at completion of Local Oscillator and Control section

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  • wa2isc
    Dec 13, 2012
      --- In softrock40@yahoogroups.com, "Alan" <alan4alan@...> wrote:
      >
      >
      > ----- Original Message -----
      > Subject: [softrock40] Re: RX ensemble II No output at completion of Local Oscillator and Control section
      >
      >
      >
      >
      > >
      > > The output on the SI570 shows 1.66 V at 60 Hz and no appearant short to ground.
      >
      > Kevin
      >
      > What do you mean 60Hz?
      > About 1V5 DC is expected. And there should be RF, 3V pk-pk.
      > Have you grounded your instruments to USB ground?
      >
      > > jewelers loop tells me that the solder is OK on all 8 pins (ie, no solder bridges or missed pads. It there a way to test the
      > Si570 in situ?
      >
      > You almost have. It should have an output if it has power.
      > Check voltage on pad 2.
      > Normally 3V, unused but if it is grounded in some way it stops the output.
      >
      > 73 Alan G4ZFQ
      >
      Hi, again Alan,

      I don't have ready access to a 'scope, so I use a conbination of the Freq. counter and the Fluke. Since I was looking for AC (OK, RF), I got the 60 Hz on the circuit. I didn't look at the DC voltage. Now, I show .95 VDC on pad 4, and 0 on pad 2. Pad 2 shows infinite R, so not grounded.

      Yes, I used the USB ground for these measurements. I am lost!

      Thanks for your sage advice
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