Re: [TenTec] ARGONAUT 515 problem

[Lee <lee@wa3fiy.com>]

Rick, your DVM will be fine to check the voltage at "LSB".  The circuit 
impedance is around 1K so the DVM will have VERY little effect on the 
reading...and the actual voltage is not at all critical.  That 1K 
resistor you see on the diagram feeds "LSB" which feeds Q2 through 
another 1K resistor in series.  The voltage at "LSB" will likely be just 
under 1/2 your supply voltage or around 6 to 7 volts.
I agree with you about the puzzle about why it is switching sidebands 
between 80 and 40.  The manual states "...SB-N is the sideband normally 
in use on all bands..."  That is what I remember about using my 515 
also.
I'm thinking you may already have enough test equipment in the DVM and 
frequency counter to solve this.   The voltage at "LSB" should stay the 
same on both 80 and 40 and the BFO frequency measured at the top of R7 
should also stay the same.  Sounds like a fun projecct.   :-)
73,

-Lee-
WA3FIY

------ Original Message ------
From: "rick@dj0ip.de" <Rick@dj0ip.de>
To: "'Lee'" <lee@wa3fiy.com>; "'Discussion of Ten-Tec Equipment'" 
<tentec@contesting.com>
Sent: 9/5/2016 10:58:14 AM
Subject: Re: [TenTec] ARGONAUT 515 problem

> I haven't taken the radio apart yet, Lee.
> Yes, the LSB pin has a direct connection to +12v through a pull-up 
> resistor,
> and the mode switch grounds the pin for SB-R.
>
> Last time I worked on Argonauts I had a scope, VTVM, signal generator, 
> freq.
> counter, etc.
> Today I only have a DVM and a freq. counter.
>
> What's blowing my mind is that it works normal on 40m and reversed on 
> 80m.
> I can't see how the band would have anything to do with it.
>
> I can borrow a scope from our ham club and perhaps use a QRP rig as a 
> signal
> generator.
> I need to check how high the impedance is on my DVM.  Dunno if I can 
> use
> that instead of a VTVM or not.
>
> There's always a reason and once you find it, it usually makes sense.  
> Right
> now it makes no sense to me.
>
> 73 - Rick, DJ0IP
> (Nr. Frankfurt, Germany)
>
>
>
> -----Original Message-----
> From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of Lee
> Sent: Monday, September 05, 2016 4:49 PM
> To: Discussion of Ten-Tec Equipment
> Subject: Re: [TenTec] ARGONAUT 515 problem
>
> Congratulations on getting a 515 Rick.   Bet you'll have lots of fun
> with that radio.
>
> You are correct about leaving the mode switch in "Normal" position on 
> all
> bands normally...hehe.
>
> You probably found the problem by now but if not, check the voltage at 
> "LSB"
> on the SSB GENERATOR board.  It should be a positive voltage in "NOR" 
> mode
> and ground in "REV" mode.  Doesn't look to me like that changes on any 
> band.
> 73,
>
> -Lee-
>
>
> ------ Original Message ------
> From: "rick@dj0ip.de" <Rick@dj0ip.de>
> To: n4py3@earthlink.net; "'Discussion of Ten-Tec Equipment'"
> <tentec@contesting.com>
> Sent: 9/5/2016 8:14:20 AM
> Subject: Re: [TenTec] ARGONAUT 515 problem
>
> > Gm Carl,
> >
> > It's the other way around by me.  I leave it in "Normal" for all bands
> > except 80m.  On 80 I have to switch to Reverse.  I have owned 4 pyjrt
> > Argonauts including one other 515 and none of them worked like this.
> >
> > 73 - Rick, DJ0IP
> > (Nr. Frankfurt, Germany)
> >
> >
> > -----Original Message-----
> > From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of Carl
> > Moreschi
> > Sent: Monday, September 05, 2016 1:52 PM
> > To: Discussion of Ten-Tec Equipment
> > Subject: Re: [TenTec] ARGONAUT 515 problem
> >
> > Rick,  I think this is normal.  The mixing scheme works such that LSB
> > comes out as normal on 80 meters.  I seem to recall that my Omni A
> > worked the same way.  I think they use the same crystal for 20 and 80
> > meters to get to the IF and this yields USB on 20 meters and LSB on 80
> > meters.
> >
> > Carl Moreschi N4PY
> > 58 Hogwood Rd
> > Louisburg, NC 27549
> > www.n4py.com
> >
> > On 9/4/2016 10:51 PM, rick@dj0ip.de wrote:
> > >   Meanwhile, back at Ten-Tec . . .
> > >
> > >
> > >
> > >   I have just received an Argonaut 515 in fairly good shape, just
> > >  needing a tune-up.
> > >
> > >   However it does have one minor issue which has me stumped.
> > >
> > >
> > >
> > >   On 80m I could hear lots of strong signals but all sounding like
> > >  Donald Duck.
> > >
> > >   I switched to SB-R which should normally place the rig in USB mode
> > > and
> > >   everything worked just fine.
> > >
> > >   On 40m, and all other bands, I switch back to SB-N and everything 
> > > is
> > > fine.
> > >
> > >
> > >
> > >   I haven't checked transmit yet to see if the wrong mode is only
> > >  selected in RX or if it is also during TX.
> > >
> > >
> > >
> > >   What is curious to me is, the mode switch is labeled for SB-Normal
> > > and
> > >   SB-Reverse, yet the signal input to the SSB generator board for
> > >   switching these is simply called LSB.
> > >
> > >
> > >
> > >   What I am unable to find is how the position of the bandswitch can
> > >  pass a signal through the mode switch to tell it when to enable or
> > >  disable this LSB line.  That must be the source of the problem.
> > >
> > >
> > >
> > >   I believe  this is very similar to the Triton IV so perhaps someone
> > >  with that radio understands how this works.
> > >
> > >
> > >
> > >   Tnx.
> > >
> > >
> > >
> > >   73
> > >
> > >   Rick, DJ0IP
> > >
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