[Kenwood] TS-520SE receiver brain teaser

Thu, 26 Feb 2004 20:31:47 -0500

It almost sounds like the center pin of the PL-259, as you screw it in,
is pushing the female (SO-239) pin back a bit to either cause it to hit
something at ground or the SO-239 pin has developed a loose connection at
it's solder point. With the wire in the center connector, and you're
receiving "OK",  try using a small wooden stick or a small tipped
screwdriver and push or wiggle the center female pin of the SO-239. Maybe
the shield of the cable going to the back of the SO-239 has a wire hair
that has migrated too close to that center pin so that as you screw the
PL-259 on, it pushes the center pin back enough to touch it.

Pete, WA2CWA

On Thu, 26 Feb 2004 03:20:30 -0600 Tim Billingsley
<[email protected]> writes:
> OK I am getting mixed signals on this ...
> 
> >"There should NOT be a dead short between the centre conductor and 
> ground of the chassis mounted SO-239, make and model of radio 
> notwithstanding. It appears that there is a short inside the radio 
> (or a bad SO-239 jack) Cheers and Good Luck... "
> >
> 
> > *"A simple test of the suspected short in the radio itself, is to 
> 
> > simply attach a wire to the center connector at the radio.  If you 
> 
> > hear a signal with only the center connected, then your radio is 
> not 
> > shorted internally. " *
> 
> This is what I have setup currently and the radio hears very well
> 
> >  
> > *"The radio itself, being a tube type, will possibly show a short 
> due 
> > to the configuration of the final amplifier.  "
> > *
> 
> OK I am, as I stated, visually challenged, but from what I could 
> make 
> out the center connection of the 239 goes to an inductor and into 
> chassis ground after that ... again as I stated I may have lost 
> track of 
> the trace and could be mistaken and I do not have the schematic here 
> 
> with me, it is with the radio some 40+ miles away.
> 
> > *
> > "However, if it is truly shorted as you say, the radio will be 
> totally 
> > deft at all times. " *
> 
> This is not the case at all. The receiver picks up signals very well 
> if 
> only the center pin of the PL-259 or just a simple wire is inserted 
> into 
> the SO-239, but this does not explain the behavior of the radio when 
> 
> even a "naked" PL-259 is connected. I cannot see the PL-259 with no 
> coax 
> at all having any profound effect on the radio but in fact it does. 
> As I 
> previously stated I connected 3 different pieces of coax that I 
> verified 
> the continuity or lack thereof as the case may be between the center 
> and 
> shield and the stand alone PL-259 and all (according to the RatShack 
> 
> meter I had available) appeared to be in good working order.
> As for previous activities involving an antenna "for ham bands" the 
> 
> radio prior to being moved served me very well connected to a 40 
> meter 
> inverted "V" fed with  RG-213. The house that this radio is sitting 
> in 
> now is a late 1800's Antebellum home with Knob and Post wiring and 
> few 
> if any grounds ... not sure what bearing that may have but some of 
> you 
> EE guys may be able to shed some light on that if it applies in any 
> way.
> 
> I don't see where impedance mismatch would affect this in the way I 
> have 
> described but as I stated I am still a young fellow and I have yet 
> to 
> see it all ... on that note ...
> 
> >"*I give the details because you inferred you were a young and 
> inexperienced ham."*
> >  
> >
> Perhaps I misrepresented myself a bit ... young is a relative thing 
> I am 
> 38 and an Extra Lite ... I do not know it all by any means but I 
> have 
> been around the feed lot a couple of times and I am reasonably 
> familiar 
> with the lay of the land and where the highlights exist, but in my 
> humble inexperience I always come back to the reflectors where the 
> vast 
> cumulative knowledge and experience far exceed anything that I will 
> most 
> likely experience in the next 40 years of my life.
> 
> Thanks to all for your time and attention and if anyone has 
> additional 
> wisdom to apply to this riddle please don't hesitate to let us hear 
> from 
> you.
> 
> Good morning all and 73
> Tim
> - - -
> 
> Your moderator for this list is:
> Larry Wilson KE1HZ [email protected]
> 
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