The backbone of the Argonaut 509 are the two signals, "R" and "T".
If I recall correctly (40 years ago), they are generated on the control
board.
> In RX mode, R is positive (I believe it is something like 8 volts; it's in
the manual) and T is near zero.
> In TX mode, T is positive (same voltage) and R is near zero.
So the first thing I would do after the initial smoke test is confirm that
these two voltages are working correctly. They control most of what goes on
inside of the radio.
I assume the radio is not receiving, thus the claim that it is broken.
So the next thing is to see if the various oscillators are working.
This is best done with an oscilloscope.
There is the [roughly] 9 MHz crystal oscillator (I believe it's on the SSB
board), and then the output of the VFO. These are well documented in the
manual.
The next thing is to inject a signal into the antenna jack, using either a
signal generator, or if you don't have one, connect a dummy load to a
working transceiver, and set it for about 5 to 10 watts.
Then take a piece of hookup wire and wrap a few turns around the outside of
the coax, then connect the other end to the antenna jack of the 509. The
leakage through the coax will give you a low level signal to use for tracing
through the radio. I would start with 80m.
Using a scope first trace it at board level, beginning at the antenna jack,
then the input to the RX's RF amp, then the output of the RF amp. From
there it goes to the mixer and mixes with the VFO signal, producing a 9 MHz
signal at the output of the mixer. From there it goes to the IF amp.
So trace it through these stages until you find some stage where there is
signal on the input, but not on the output. Once you find that, you have
localized the "first" point of failure. (hopefully the only one)
It will take some blood, sweat, and tears, but once you get it working
again, you will be a proud, happy camper!
Gud Luk.
73,
Rick, DJ0IP
(Nr. Frankfurt, Germany)
May the Sunspots be with us!
-----Original Message-----
From: TenTec <tentec-bounces@contesting.com> On Behalf Of Ron Notarius W3WN
via TenTec
Sent: 08 September 2019 21:18
To: 'Discussion of Ten-Tec Equipment' <tentec@contesting.com>
Cc: Ron Notarius W3WN <wn3vaw@verizon.net>
Subject: [TenTec] What Have I Gotten Myself Into?
Spent a little time at a small hamfest about an hour from home. There on
the club table, much to my surprise... an Argonaut 509 for $10. 00.
That's not a typo. Ten Dollars.
It was quickly explained to me that the unit was "not working" (no specifics
given) and "needed some help", and the price included several small bags of
parts. (No manual, so I'll have to download one)
I just couldn't pass it up, not at that price. But now I'm wondering...
what have I gotten myself into?
Any tips on where to start with the poor thing will be appreciated.
...oh, also on the table was a Ten Tec 1553 Budget Electronic Keyer Kit,
never opened, $5 and yes that went home with me! Unfortunately, the Orion
II kept calling to me, but $1200 was just more than I had in my wallet. (To
say nothing of the ETO Alpha 87 for $1300)
73, ron w3wn
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