Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net

   Home   Help Search  
Pages: [1]   Go Down
  Print  
Author Topic: TS-140S SWR Protection?  (Read 1773 times)
KI4OGD
Member

Posts: 12




Ignore
« on: December 27, 2007, 08:56:16 PM »

HI, I have A Kenwood TS-140S that I think is enabling SWR overload protection.  It is putting out only about 10 watts.  My first fear was blown finals, but 10 watts seems like a weird (read, high) level to go into the PA stage.  the power slider is good, but only drops transmitter power in its bottom quarter of its length.  Only meter I have is the one in the radio, and I am about 1200 miles away from the rig without a dummy load at the moment, but I wanted to get a consensus if it is possible I am looking at a protection circuit, or if I should be looking for a new rig.
Thanks
Steven, KI4OGD
Logged
K8GU
Member

Posts: 718


WWW

Ignore
« Reply #1 on: December 28, 2007, 08:36:30 AM »

Well, there are a number of possible situations.  First, you really need to test it with a dummy load and an external meter.  What kind of antenna are you using?  I'm not intimately familiar with the TS-140...does it have a switch to read the internal SWR circuit on the meter?  That's a pretty good way to verify that it's an SWR protection situation.  Also, are you sure that the radio is not the 10-watt version TS-140V? ...or a TS-140S with the PA from a TS-140V?  (I don't know if the latter is possible; but, it's worth suggesting...)
Logged
WA9SVD
Member

Posts: 2198




Ignore
« Reply #2 on: December 30, 2007, 06:14:15 PM »

Curious; the Service Manual (not owners manual) doesn't even mention a "TS-140V."

    What mode are you using?  The only real way to check is with a dummy load and in CW mode.  The slider controls are the one, BIG weak point of the TS140/680 twins.  You should "exercise" the power control several times, the power shouldn't be controlled at just one end of the control.  Also, do the same with the "mic gain" control if you use SSB.  Dust and oxidation can make the sliders very intermittent, if not adjusted or moved occasionally.  the radio WILL start to reduce power when the SWR reaches 2.0, but I suspect that's a nominal figure, and individual radios may be a bit more sensitive to SWR than others.
    See if you can at least borrow a good dummy load and SWR bridge or wattmeter from a local Amateur.
Logged
KI4OGD
Member

Posts: 12




Ignore
« Reply #3 on: January 01, 2008, 07:06:51 AM »

The radio has been sitting in a dusty closet for quite awhile, and may have been operated by non licensed or highly inexperienced ops (collegiate club radio station), It's away from me right now (I'm in Northern Virginia, it's in central Tennessee), so I'll let you now what I find when I get back.  There is a Heathkit Cantenna on site, and I can get a wattmeter /swr bridge fairly easily.  I'll try cleaning the sliders for PO and mic gain when I get back as well.  

Thanks for the input from all, I will keep you posted.
Steven KI4OGD
Logged
K8GU
Member

Posts: 718


WWW

Ignore
« Reply #4 on: January 01, 2008, 09:41:17 AM »

Good luck with that and let us know if you have more questions.  I doubt that it's the 10-watt version given the situation you describe...they're pretty rare in the States anyway.

To WA9SVD, your comment sent me to Google to ensure my memory wasn't faulty...from the Kenwood JA website:

http://translate.google.com/translate?hl=en&sl=ja&u=http://www.kenwood.com/j/products/amateur/kouji/hf_allmode_frame.html&sa=X&oi=translate&resnum=3&ct=result&prev=/search%3Fq%3Dts-140v%26hl%3Den%26sa%3DG

I don't know why that's not mentioned in the Service Manual.  My TS-930S Service Manual doesn't mention a TS-930V...which I've never heard of, although it's listed on the Kenwood page above...
Logged
WA9SVD
Member

Posts: 2198




Ignore
« Reply #5 on: January 16, 2008, 09:05:18 PM »

K8GU:

    Apparently the TS-140V was never marketed in the U.S.  The version of the TS-140s sold in Europe is apparently power limited on the 160 Meter band; the Service manual available from Kenwood U.S.A. did not mention any such version or variant.  The Service manual available in Eurpoe is apparently very different, and includes instructions in several languages; the U.S. manual is only in English.  The U.S. manual covers the TS-140S and TS-680S, but mentions no variants or different versions of the radios.

 Just as a comment, there's no apparent way to tell the differences in the vatious manuals (or radios) that I know of short of comparing the schematics side-by-side.

    However, if the radio actually says "TS-140S" then it should produce 100 Watts.  (Unless it is somehow the European version, and measurement is made on 160 Meters!)

    But my bet is the slider power control has dust that is preventing a good contact from being made.
Logged
Pages: [1]   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!