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Author Topic: ten tec argosy 525  (Read 17182 times)
M0JHA
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Posts: 646




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« on: November 10, 2013, 06:52:07 AM »

Hello, I have just bought the above radio as a non worker from a mate , he got it off an old timer who said it was working and the VFO just needed re stringing whatever that is . anyway when he got it it keeps tripping fuses . He doesn't know a lot on electronics as I don't so he sold it me and I was going to have a bash at fixing it if it wasn't too complicated a job . I think it was sent via post so maybe something has been jolted loose ..

Anyway is there any known faults that could be causing this ?

Thanks in advance for any info

billy
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KB4QAA
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Posts: 3342




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« Reply #1 on: November 10, 2013, 10:54:13 AM »

Have you got the manual?  If not you can download from the Ten Tec site.
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KA0HCP, ex-KB4QAA Relocated to Ks. April 2019.
M0JHA
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Posts: 646




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« Reply #2 on: November 10, 2013, 11:58:39 AM »

There is a manual with the radio but I havn't got the radio as yet as it's in post . I just thought I would put some feelers out in case there were any common problems along these lines.

billy
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W9GB
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Posts: 3380




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« Reply #3 on: November 10, 2013, 12:58:19 PM »

Billy --

TenTec 525, Argosy : Owners Manual (Ten Tec web site)
http://74.220.205.254/files/Argosy%20Model%20525%20Manual.pdf

Contact G3TXQ (Good Elmer, what you need for the Argosy project)

G3TXQ -- DIY Build of the TenTec Argosy Mark I (525)
http://www.karinya.net/g3txq/argosy_copy/

SE HUNT, G3TXQ
21A Green Street, Milton Malsor
Milton Malsor, NORTHAMPTON NN7 3AT
England
====
Argosy 525 PTO (and Dial String)
http://www.k9ew.us/525_pto.htm

Ten Tec PTO Rebuild Tips & Links
http://www.tentecwiki.org/doku.php?id=pto

Upgrading the Ten-Tec Argosy 525
Achieve better noise floor and "crunch-proof" performance
Scanned from: Ham Radio Magazine, Pages 38-50, November 1986
by KW7CD
http://www.qsl.net/tentec/mods/525mods.htm
« Last Edit: November 10, 2013, 01:13:15 PM by W9GB » Logged
AA4PB
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Posts: 15066




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« Reply #4 on: November 10, 2013, 01:08:28 PM »

"the VFO just needed re stringing whatever that is"

Replacing the dial cord that operates the VFO dial pointer. If it's broken they the pointer won't move as you turn the VFO.
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Bob  AA4PB
Garrisonville, VA
M0JHA
Member

Posts: 646




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« Reply #5 on: November 10, 2013, 01:29:56 PM »

Thanks chaps, @ AA4PB , thought it was something along those lines , thanks for the link that will be useful.

@W9GB again thanks , I have spoke to Steve many times regarding all manner of antenna subjects , I messaged him earlier re the rig as I know he has had one and made his own version but he stated they are pretty simple to work on . I will wait till the rig arrives then I know exactly what is happening ..

cheers again

billy
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WB6BYU
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Posts: 18527




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« Reply #6 on: November 10, 2013, 01:36:26 PM »

A shock to see the Argosy being called a boat anchor!  I have one of the first
ones, SN #99.

There are at least 2 versions with different receiver mixer circuits and some other
changes, but generally that shouldn't affect your current task.  Front-end overload
was a real problem with the earliest version that used a MC1496 mixer; that was
then changed to a diode ring mixer.  (I ordered parts to upgrade mine based on a
magazine article, then discovered the mixer circuit was entirely different than the
one in the article.  In the end I bought an RF board for the 525D from Ten-Tec
and swapped them out.)  The diode ring mixer is much better, though still some
room for improvement.

Restringing the dial isn't as trivial as it might sound - it uses a length of elastic
cord in place of a string, and the cord degrades over the years.  Replacement
elastic cord is available from Ten-Tec.  After having done it 3 times, that is still
the main reason I'm not using the rig as much these days.

Basically the dial string couples the VFO drive shaft to the little red pointer that
runs across the dial and tells you which 100kHz segment you are tuned to.  (The
dial plate on the knob reads out the frequency within each 100kHz segment.)
Next time I open it up I'm going to cheat and mount a digital display behind the window
in place of the pointer.

But they are a great rig!  It doesn't cover 160m, 17m or 12m, and only puts out
50 watts.  As is the case with many Ten-Tec rigs it is designed to be used with
a matching power supply that includes over-current shut-down, otherwise you
need to add a fast-acting magnetic circuit breaker in the DC line to help
protect the finals.  (Voltage limiting is handled by the ALC circuit, while current
limiting is handled in the power supply.)  The Argosy does NOT shut down based
on SWR as many rigs do - instead it limits the voltage and current on the finals
(which are what causes the damage to the transistors, along with overheating.)

I still find it better than listening to my newer synthesized rig for weak CW signals -
it doesn't make my ears ache.


The first step is to figure out what is causing the fuses to blow.  It could be as
simple as having the key plugged into the wrong RCA jack on the back of the
radio.  Or the finals could be shorted, which can be a serious problem - the last
time I talked to Ten-Tec about it they told me replacement finals were unobtanium,
but you might be able to dig something up.

Note that at least the older version operates QRP by bypassing the final stage, so
even if the finals are bad you can still use it to get on the air using the driver stage.

The good news is that it is fairly easy to work on - all through-hole parts, and most
of the boards can be removed for repair.  Just keep track of all the little plugs and
where they go when you remove a board.  (You may want to go through and wiggle
and/or remove/reinsert all the plugs to reduce any potential problems with poor
contacts due to corrosion build-up over time.)


Going from memory, the first step might be to unsolder the main power lead from
the amplifier board and insulate it so it doesn't short.  That should allow you to
check out the rest of the radio - if the fuse stops blowing, you've at isolated it
to one board.
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W9GB
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Posts: 3380




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« Reply #7 on: November 10, 2013, 02:15:27 PM »

Information from the Ten-Tec Reflector July 7, 2000
http://www.qsl.net/tentec/specs/525.jpg

Ten Tec model 1140 and 1170 magnetic circuit breakers.
http://www.tentecwiki.org/lib/exe/fetch.php?media=1140_1170flyer.pdf

Those breakers were made for Ten-Tec by Airpax.
Airpax part number is T11-1-20.0A-01-10A-V (Ten Tec 1140)
Airpax still makes dozens of breakers…….. the series mfg for Ten-Tec
is the Snapak model magnetic breaker.

To replace the 1140 model, Ten-Tec recommends an Airpax T-11 20 amp fast acting breaker
 available from Wards Electronics in Florida, (800) 545-9273.

Airpax breaker part number should be:

T11-1-(required amperage 3 places)-01-10A-V

example: T11-1-5.00A-01-10A-V

T11 = Paddle Handle, Single Pole, Series Breaker
1 = "fast" trip (0 =instant and 2 = slow…… 2 is too slow 0 would work fine too)
5.00A = 5 amp
01 = Paddle Handle is Black
10A = Black Knurled Mounting Nut
V = Vertical Mount

Enter in the original amperage of the breaker you are looking for and
this number should be close if not right on to the original……
Ten-Tec's Service Manager, Paul Clinton earlier stated that
either the fast or instant breaker would work fine…..
The breakers sold for the Ten Tec Triton IV, some were fast and some were instant.

Best place to find them (they are hard to find) at the best price ($25 min order - Airpax has a $500 minimum) has been Poco Sales: http://www.pocosales.com/
« Last Edit: November 10, 2013, 02:19:26 PM by W9GB » Logged
W9GB
Member

Posts: 3380




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« Reply #8 on: November 10, 2013, 02:23:16 PM »

Final Transistors (PA) used in the Ten Tec Argosy 525 are the Motorola MRF 477 (used 2).

This was a popular RF transistor used in CB transceivers (Uniden HR-2510) during 1970s and 1980s.
http://www.hgsemi.com/case.asp?id=13

Replacements are available from HG Semiconductor in China.
They are now manufacturing the HG 477 RF transistor.
http://www.hgsemi.com/case.asp?id=1

HG Semiconductor
http://www.hgsemi.com/Aboutus.asp?id=1
Postal Address: West 2nd Floor, 2# Buliding, 88 Qianyao Road, Wuxi, Jiangsu, China
Postal Code: 214151
Head Quarter Tel: +86-510-81023902
Shenzhen Sales Office: +86-755-61285520
Fax: +86-510-81023909
E-mail: north@hgsemi.com (Reply in 24 hours)
« Last Edit: November 10, 2013, 02:44:15 PM by W9GB » Logged
M0JHA
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Posts: 646




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« Reply #9 on: November 11, 2013, 09:34:17 AM »

Thanks for all the info chaps , that will get me started . i will update the post for anyone interested when i have received the set and had a look to see what is going on with it for myself , no doubt i will be back with more questions but looking forward to having a crack at sorting the set out ..

here is the original add

"Ten tec Argosy in need of repair i took this on as a project and I have looked at (not touched ) anything and to be honest its beyond my limited skills when i got this i was told the vfo needed re-stringing when it arrived the radio doesn't work it is giving too much voltage out even when switched off so bare this in mind the radio doesn't work in its present condition over all its very clean and tidy and will make a nice radio it is orginal 525 not the D I want this radio to go to someone who will restore the set or get it restored or you need one for spares no part stripers out to make a quick quid on ebay or anyone wanting a quick flip and sell on e  bay id rather just sit it in the cupoard as i took this on as a restore project not to make money on it i am open to deals on the radio just send me a pm would prefer face to face and ill throw in the psu that came with it"

not sure if that rings any bells for anyone ..
« Last Edit: November 11, 2013, 09:48:10 AM by M0JHA » Logged
KE6EE
Member

Posts: 2814




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« Reply #10 on: November 11, 2013, 12:16:10 PM »

here is the original add

"Ten tec Argosy in need of repair i took this on as a project and I have looked at (not touched ) anything and to be honest its beyond my limited skills when i got this i was told the vfo needed re-stringing when it arrived the radio doesn't work it is giving too much voltage out even when switched off so bare this in mind the radio doesn't work in its present condition over all its very clean and tidy and will make a nice radio it is orginal 525 not the D I want this radio to go to someone who will restore the set or get it restored or you need one for spares no part stripers out to make a quick quid on ebay or anyone wanting a quick flip and sell on e  bay id rather just sit it in the cupoard as i took this on as a restore project not to make money on it i am open to deals on the radio just send me a pm would prefer face to face and ill throw in the psu that came with it"

not sure if that rings any bells for anyone ..

The bell which rings for me is my high school English teacher pointing out a gem of a run-on sentence with some notable spelling and punctuation errors.
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WB6BYU
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Posts: 18527




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« Reply #11 on: November 11, 2013, 12:38:21 PM »

Quote from: M0JHA

... ill throw in the psu that came with it"



That's an important bit - it should be a Ten-Tec 251 power supply I expect with
the internal over-current protection.  Make sure it is working first - if there is
a problem in the over-current protection circuit it can shut the rig down at much
lower currents, which would look like the rig '"blowing fuses".  And if it is putting
out too much voltage, as the ad says, then it is probably triggering the crowbar
protection inside the power supply, shutting it down.  Some voltage measurements
should lead you to the problem.

Typically you have to short a couple pins on the DC power cable to turn on the
supply, then you should see a clean regulated voltage on the output.  It should
be able to deliver 10A without problem, then shut itself off abruptly at 11A or so.
(Once it does, you have to shut it off and turn it back on again.)  A reasonably
check would be an auto headlamp (I save the dual-beam type with one filament
burned out for this purpose):  it probably can light one lamp but not two at the
same time.

Note that the switch wiring from the power supply to the rig is the full mains
voltage:  if you don't need to turn the supply on and off from the front panel
control then it is safer to jumper the connection internally and disconnect
the wires - I don't like having mains wiring mixed in with the main DC power
in case there is a short somehow.  Once you do this then you can turn on the
DC supply without having it connected to the radio.
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G3RZP
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Posts: 1319




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« Reply #12 on: November 11, 2013, 01:08:43 PM »

N6GND

'English' as such, meaning grammar and spelling, hasn't been taught here for at least 20 and probably 30 or even more years. The 'progressives' (those of us who considered biased would call them 'lefties') consider it unnecessary.....Not having any children that I know of, I'm not up to date on modern education standards - such as they are.
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KE6EE
Member

Posts: 2814




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« Reply #13 on: November 11, 2013, 04:44:08 PM »

N6GND

'English' as such, meaning grammar and spelling, hasn't been taught here for at least 20 and probably 30 or even more years. The 'progressives' (those of us who considered biased would call them 'lefties') consider it unnecessary.....Not having any children that I know of, I'm not up to date on modern education standards - such as they are.

English isn't taught here, either. Or spoken for that matter. In schools these days young people are taught subjects, using a computer of course, like creative writing, journaling (not to be confused with journalism), rapping, poetry and assuming the guise of an artist (and/or gangbanger [=American English for criminal mastermind]). Mastery of a language is not important, nor is the effective use of references like dictionaries. Googling is encouraged, but not often done.

N.B. a bit off-topic, sorry, but humor is a daily need in my life.
« Last Edit: November 11, 2013, 04:46:12 PM by N6GND » Logged
M0JHA
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Posts: 646




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« Reply #14 on: November 12, 2013, 02:20:57 AM »

Thanks for all the useful information chaps . very much appreciated .

billy
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