Argonaut 509 - Repairs and touch up... July 5th 2013

This article is still being written ..73 Earl VE3AB - The art of
improvisation is still alive and well in the ham radio circles. I
don't build from scratch..(though I want to build something
relatively complex from scratch)..but I do repairs and this
fellow in USA sent me this Argonaut (that has sentimental
value to him). I did some basic repairs and touch ups. - July 2013 Article.
Number one on the to do list..was to restring the dial. There are other articles from
my web pages that show the process of restringing the I wont go into it
this time. You will notice that I used a cursor that is metal and had to adapt it a bit
to the Argonaut 509. It worked very well. I am in the process of ordering more
cursors and clips and a PTO rebuild kit and PTO grease and other parts from Ten
Tec in the next week or two.
Above Pictured..the PA final stage. This Argonaut 509 (I have finished working on
it now and have sent it back to the ham in USA - 7 July 2013 - This PA stage has
these blue toroid cores. I have seen these toroids before and I have some of
this color in my collection. Im not sure what mix they are-- I have some test
equipment to measure inductances and I may try and figure out some of the
mystery toroids in my collection

Argonauts such as the 505 through 515 are all discrete components like
transistors,resistors and capacitors and coils. There are several ICs as well..but
they are older linear ICs that are rather basic by todays standards. The good part
of all the rig is easy to figure out and relatively easy to fix the electronics.
I had to replace the dual gate mosfet RF amp stage. I decided to put in a homebrew socket under the board..(where there is a bit more finger room).
I do this with all my Argonauts when on the bench. Unsoldering the original dual gate mosfet is a pain in the butt. Sometimes they will get damaged
from static on the antenna-- and sometimes you want to experiment with a higher gain dg mosfet. (I think!) a 3N211 would make for a hotter receive.
I went out and bought about a dozen or so (I sell them for $5 each)..which is cheaper than almost anywhere. Notice how the legs are bent over
backwards over the body of the transistor. Strictly not KOSHER!!!? - however..we Amateurs like to improvise! - I improvise and I document the repair
or mod or quirk on my pages. This fellow in USA can look over these pages at any time concerning his rig. -- I CHARGED 5 hours labour on this little
job and that only amounts to $50 in my little retirment -- one man shop. I just sent the rig back and it cost me $44.34 by post office which included $300
in insurance. IF YOU SEND ANYTHING TO ME FOR sure to use the POST OFFICE NOT commercial courier! UPS is a NO NO! Reason: they
charge brokerage fees and taxes and even tax on the tax.  
Above..pictured left is the Transceive - Receive switch. NOW..don't assume it is wired according to original Ten Tec factory or according to the
schematic!!! - Don't assume anything with these older radios. Many modifications and custom wiring jobs have been done to older ham radios
like these and best be sure to trace the circuit out. - This one is wired correctly. NOW..if the switch is in receive position..there will have to be a
separate receive antenna plugged into the jack in the will hear almost nothing. This separate receive jack is handy for
using a small low noise loop for receiving. What I did for this repair..was to put a piece of tape over this switch to make sure it is locked in
Transceive Mode.
1x40 Pin Single Row 2.54mm Round Female Headers are used (quite often by me) in order to make homebrew sockets for parts (especially transistors). The ones I
made for the upside down dual gate above..were made using 4 of these pins that were stripped completely of the plastic and I soldered them directly
to the foil side of the board. The dual gate mosfet was flipped upside down and plugs in to the socket fairly easily. -- The Circuit board..(right) is the PA final stage
from one of my Ten Tec Argonauts. I have been experimenting with different transistors and plugging them in makes it easy to change parts quickly. The down side is
the transistor leads must be cut to size carefully so as to allow the heatsink to mount with the proper clearances at the Argonaut back panel chasis.
More INFORMATION ON THE PTO.. UPDATES from both TEN TEC -- I am in process of
ordering spare parts (PTO KITS - Argosy 525 and Argonaut 509 - and other parts from them.
Dear Earl:

Dial string kits contain dial string, stretch cord and clips. Dial string kit is $1.50. We now have white plastic dial pointers. Dial pointers are $3.50 each.

PTO kit with proper grease is $35.00. Grease is  no good without a PTO kit. Grease is no good without a PTO kit. A PTO can not be greased and not
change parts and operate properly. Use  a 1N4007 for D3. Main tuning knob without silver decorative insert (no longer available) is $5.00. No other
original knobs are available. Shipping would be $15.00. Sorry, we do not accept Pay Pal, we take Visa, Discover, Master Card or American Express.

July 5th 2013. --- Above email from Ten Tec. -- They gave me some useful information. -- According to them.. A rebuild of the PTO is the
only proper way to get the PTO up and running again! --
- I had read (and perhaps even reported on my other Argonaut pages..that some
fellows have used lighter fluid or 50 pct pure alcohol and 50 pct WD40 to thin hardened PTO grease ..then they used new grease and got
the PTO going again. -- Well..Ten Tec recommends buying the PTO rebuild I am going that route myself with my one Argosy 525 and
my other two 509s with wonky PTOs. ---
I read (very recently) on the internet..that WD40 should not be used on BRASS!!! The PTO metal
parts are brass... --
So this is the latest I have on the situation. -- I am going to phone my order in for parts Monday.

**** The PTO of this Argonaut 509 I just recently worked on was working fine so I left it alone.
A 'protective diode circuit' for the 509 -- also can be used for other radios as well. I first saw this circuit in the QRP
Quarterly magazine. -- The Argonaut only has 2 diodes back to back...and (according to the magazine
article)..strong foreign BC stations on 40 meters (for example)..can overload the 2 diode system. Using 4 diodes in
a 1.4volt 'clamping' protective circuit..on the receive line comming from the TR/antenna relay and going to the
front end (dg mosfet) in this case..can save the more delicate mosfet from static or spike damage. -- The 4 diode
system might be a bit more rugged as well.
More to be written here shortly..

this article is being worked on July 5- 2013!
Now comes a bit of a tricky part..getting the dial skirt on again. I used my fishing line and with one well timed pull of the loop/string and
a bit of a push on the dial skirt..It went on first time and easy.
This Argonaut 509 I was working on here most recently... seemed to be much higher average power output than the average run of the mill Argonaut.
On 80 it was about 4 watts out and on 40 was over 6 watts output or maybe a bit more. 20 and 15 were high as well..about 6 watts or so. 10 meters
measured about 3 or a bit more on my Oak Hills research WM2 Watmeter using the 10 watt scale. I did not want to take the time to check out why
exactly the output was so high. I did some looking around at the rig while I was doing the basic repairs and check out..but..I thought..leave well
enough alone!! It worked good and why tempt fate by pulling off the heatsinks on the PA transistors -- I could break a lead or something.
Now..what I would do..if I were the user of this to
tune up with lower power..less qrm on the band..and I would
use an external wattmeter to monitor the transmit power my WM2 for example.

If..I wanted to do a simple mod so that the meter would not
pin to the end of the scale-- I would do it as per the
schematic shown left. -- You would have to break the line on
the circuit board (output from T1 primary winding).

You could (at this break) insert a 1 kilohm variable trimmer
resistor (non-inductive) - a small trimmer would do.

You could either leave the trimmer in place..or remove it and
insert a 1/2 or 1/4 watt carbon composition resistor of the
value measured to create a desireable meter movement.

I have one Argonaut 509 in my collection..that has the higher
powered PA transistors in it and I plan to do this mod in the
very near future and I will take some pictures.

This 509 I have (I now own 4 -509s) is different. It is very very
clean looking circuit boards. Almost like they were
manufactured in the 1990s or something. The PA stage has 2
MRF476s (just like the 515). Im thinking this Argonaut was
manufactured just before Ten Tec switched over to the 515
and/or it was modified by a previous owner with a 515 board
in the final stage.

Anyways.. I want to do this meter mod and I will be doing it in
a very non destructive manner! -- I will post pictures when I
do it.

Also..the PTO is non functional.. very poor operation and I am
ordering a couple of PTO rebuild kits and other parts from
Ten Tec in a couple of days time.

Stay tuned..73 Earl ve3ab
There are two meter adjust potentiometers on one of the circuit boards of the 509.
One is to zero set the meter. The other is to adjust the S meter. Neither one does
anything for adjusting the RF output indication of the front panel meter.

Another possibility is to reduce the coupling of the link winding on the T1
transformer..but I think the potentiometer option would be the better choice.

It might be possible to adjust a potentiometer so that the meter would give the
power output (in a perhaps more accurate relative way). Full Scale might be 7
watts out..half scale 3.5 watts out...something like that. Perhaps some
experimentation ..trial and error could be done.
Modification to the 509 Meter circuit (relative power indication) so the meter does not 'Pin"when
running higher 4 watts or more
I had to replace the dual gate mosfet (receiver RF amplifier) because..of my error. I had a scope probe
with an exposed ground lead and I touched something that caused a bit of a problem.. I of course, owned
up to my mistake and I replaced the dg mosfet with labour FREE OF CHARGE.
----->> I have plenty of DG Mosfets and I sell them for $3 for a 40823 and $5 for a 3N211 (while supplies
last). -- I would like to try a 3N211 in the front end of the Argonaut. Should make the receive a bit more
sensitive for digging out those weak signals.
Hi Earl, I'm here again. Thanks for writing on Argonaut 509, it's always a pleasure to gain information about vintage equipments, and I am an incurable
romantic piece of antique.....
My Argonaut works well but I think I have to put the hands on the string...soon or later, the index does not reach anymore the left side of the dial, close to it
but not perfectly aligned on zero.....just few millimeters to the right and the frequency, when close to zero, on 14 Mhz,  is 13.770, but it's  not a big more thing....when the index is completely to the right, it reaches.....the middle of the meter.....very funny. I've never replaced the string until
now, may be is better to wait....or do it.
Thanks again for your patience Earl.

On Jul 7, 2013 5:36 PM, "Earl Andrews" <> wrote:

Ok George thanks for the good wishes. I have never had any problems with the linkage yet. I guess it is pretty rugged.
(my note here: George did ask me if I ever had problems with the mechanical linkage which links the two switch sections of the wafer switches and forms
the band switch assembly.

I wrote Ten Tec for some 509 parts last is what they said in reply: (

---> I will be ordering above parts on Monday by phone. Looks like they still stock PTO kits (I need 2 here and am thinking of ordering maybe 3 just in
case)... looks like the parts supply is drying up. People have been writing me looking for knobs and front panels and stuff like that for rigs. I have some
junker FT301s but the older Argonauts are such sentimental old favourites that they

don't get junked. They are pretty easy to fix generally.

I think I will look in to ordering one or two bandswitch linkage parts ..just in case.

73 tnx for writing ..Earl ve3ab
Thanks to George in USA for writing me a few
interesting emails in the last few days..see below
paraphrase of the correspondence.
Hello Earl. First of all welcome again between all of us, retired for the second time.....and more time for fishing, radios and so on.
60 is not so much, and take into consideration that I'm now 68, you are a young boy, 8 more makes a big difference...anyway thanks, thanks again for
your information so kindly released. Your new web page is very well done. The added potentiometer is not a bad idea and may be I'll make the
modification one of these days...but the problem is on my mind only....for if I use an external wattmeter and switch on reflected I do not need the mod..
Argonaut 509 is really a beautiful radio, sometime I do not agree with some mechanical solutions, i.e. The band switch and the plastic connection in order
to move the other missing side of the band switch.....soon or later the two plastic pieces will break....and then? May be is time to find a suitable solution.
Did you had any trouble with it?
Thanks again Earl, all the best and good luck for your new life.
'73's de
George IK0xxx -- NOTE: i Dont publish full identities other than my own identity!!!

On Jul 6, 2013 9:16 PM, "Earl Andrews" <> wrote:

Hello George. Thanks very much for the question and it is most pertinent to me..because..I just finished working on an ARgonaut

509 for a USA ham and it runs over 5 watts out and the meter does pin most of the time when in forward position and running full power.

As a temporary thing..I would run the 509 with the meter in the reverse position. You will still see relative power output and the meter will be better served
in the very long run by doing this. -- Meters do konk out from abrasion wear. Small pieces of metal can jam and cause the meter movements to stick..and
you have to tap the front to get it to zero. I had this happen on an older Yeasu Antenna tuner. -- The Argonaut meters seem very rugged and Ive never
had a sticking meter with an Argonaut Ive had my hands on yet!

---> Now..there are 2 pots for adjustment of the meter. One is for S meter adjustment and one is for zero adjust of the meter. These pots are together on a
circuit board. -- Neither one addresses your particular issue. I decided to post a solution on one of my web pages (near the bottom). The page is the
newest Argonaut page I just wrote the other day and you can find it at the top of the articles section near the top of my web page. - I drew a schematic and
did some commentary. The name of the page is 509repairz  (
this is the page you are on right now...note by Earl VE3AB)

can navigate to that page either with www dot earlandrews dot com or www dot hamelectronicsmagazine dot com/509repairz

-- These are mirror sites with Yahoo Small Business account I use.

As for my job!! - WELL..I am now getting a second retirement pension as I just turned 60 here in are such that I don't really have to work.--
I do the odd repair and run the web pages both the above two sites and my new outdoors site: www dot earlandrews dot info. When I make a few bucks
(and I do mean a few bucks only!!!)..I put the money into my web sites and amateur radio shop supplies and parts and it is either a part time
business that is constantly in the red or a hobby!!! I prefer to call it a hobby. -- I plan to publish this email on my site ( I don't publish the names and calls of
other hams for privacy)..but I do write up problems and general inquiries I can say it is a kind of magazine..or blog or
Time to wrap things up so to speak. VERY IMPORTANT..the most damaged
part I have heard of is the Main Tuning dial. Several people have written me
for dial parts because the Main Tuning dial got smashed in through shipping.

Right now..I have an Analog Argosy 525 that I bought from Eastern Canada
and it arrived with the PTO (dial) busted quite badly. The rest of the radio is

I am going to try my DDS vfo with the Argosy 525 and abandon my previous
experiment in adapting the Argonaut 509 to a DDS vfo. The Argosy is much
simpler to adapt to a DDS vfo and there is a little movie that shows a 525
after having a DDS vfo transplant. -- The other Argonaut 509 will be restored
back to being a full fledged 509 again.
Navigation link back to my home
page..Amateur Radio/electronics and parts/ (OR).. --
73 Earl VE3AB