Re: Ensemble RXTX - no RF from SI570
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
--- In firstname.lastname@example.org, Malti <pawlud@...> wrote:
> 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
> 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.
> 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
> > ??
> > >