ICOM IC-765 Receive Sensitivty - DEAD
 

Hello,

I have an Icom IC-765. Recently, after we moved, I setup a random longwire
antenna up outside and coupled it and ground to a length of 213/U and
attached it to the SO-239 port on the back of the 765. I got absolutely NO
receive signal/sensitivity whatsoever. Even on 10 and 15 mHz. I knew this
could not be right. I checked the coax and PL-259 for a short - no problems
there. I attached the antenna to another receiver and it was definitely
pulling in signal. So, I then rigged an RCA phono plug and attached the
coax center lead to the Receive Only Antenna jack just below the SO-239 and
the receive signal shot to a full quieting WWV signal on both 10 and 15
mHz!!

So, clearly something has happened to the antenna path from the SO-239
inward. I popped the top and could see no visible solder breaks in and
around the SO-239 backside. I suspect that the problem is occurring
somewhere in the antenna tuner (well, maybe) as I think I understand that
the receive only antenna jack bypasses the antenna tuner.

Has anyone experienced this before? is it fixable by modest mortals? It is
a pain (and $) to ship the unit to Icom, so, I was hoping someone here might
suggest some possible things to try first.

Thanks!

Mark Bailey, N4XHX


__________________________________________________ ______
Mark J. Bailey Jobsoft Design & Development, Inc.
104 Arlington Place, Suite 100 Franklin, TN 37064
EMAIL: WEB: http://www.jobsoft.com/
Medimation / CardShot(tm) http://www.medimation.com/
VOICE:(615)904-9559 FAX:(615)904-9576 CELL:(615)308-9099

ICOM IC-765 Receive Sensitivty - DEAD
 

Mark Bailey wrote:
Hello,

I have an Icom IC-765. Recently, after we moved, I setup a random longwire
antenna up outside and coupled it and ground to a length of 213/U and
attached it to the SO-239 port on the back of the 765. I got absolutely NO
receive signal/sensitivity whatsoever. Even on 10 and 15 mHz. I knew this
could not be right. I checked the coax and PL-259 for a short - no problems
there. I attached the antenna to another receiver and it was definitely
pulling in signal. So, I then rigged an RCA phono plug and attached the
coax center lead to the Receive Only Antenna jack just below the SO-239 and
the receive signal shot to a full quieting WWV signal on both 10 and 15
mHz!!

So, clearly something has happened to the antenna path from the SO-239
inward. I popped the top and could see no visible solder breaks in and
around the SO-239 backside. I suspect that the problem is occurring
somewhere in the antenna tuner (well, maybe) as I think I understand that
the receive only antenna jack bypasses the antenna tuner.

Has anyone experienced this before? is it fixable by modest mortals? It is
a pain (and $) to ship the unit to Icom, so, I was hoping someone here might
suggest some possible things to try first.

Thanks!

Mark Bailey, N4XHX


__________________________________________________ ______
Mark J. Bailey Jobsoft Design & Development, Inc.
104 Arlington Place, Suite 100 Franklin, TN 37064
EMAIL: WEB: http://www.jobsoft.com/
Medimation / CardShot(tm) http://www.medimation.com/
VOICE:(615)904-9559 FAX:(615)904-9576 CELL:(615)308-9099

Mark, one quick thought here. When you contact an antenna to the
so-239, you need to have the 'rcv ant out' jumpered to the 'ant in'
phono plug to bring sigs into the reciever. Good luck.

Gary
ka9rao

ICOM IC-765 Receive Sensitivty - DEAD
 

Well, very glad you mentioned that as I had forgotten that I had removed the
jumper during the move. I grabbed it, but, still no change! :-( So, it
looks like the issue will prove more problematic. Icom had a KB item
#5BBA49629A that talked about replacing Tuner Relay Unit relay RL13
(LY2-0-DC12V). I wonder if there is any way to determine that this might be
the culprit without dismantling the Tuner Unit (sort of a pain it
appears)???

ICOM IC-765 Receive Sensitivty - DEAD
 

Gary,

FWIW, I found a PDF of the Service Manual for 765 and a Yahoo Group that had
some good threads on this very problem. Seems likely that my problem is a
failed RL201 relay on the Antenna Switch Unit. I was able to easily get the
Tuner Unit out (after finding those threads) and pull the Tuner Unit with
RL13 out of the loop and found that the relay RL201 which switches the tuner
out on Receive worked on one side and not the other.

So, hopefully replacing that relay will do the trick!

FYI

Mark

ICOM IC-765 Receive Sensitivty - DEAD
 

Mark Bailey wrote:
Gary,

FWIW, I found a PDF of the Service Manual for 765 and a Yahoo Group that had
some good threads on this very problem. Seems likely that my problem is a
failed RL201 relay on the Antenna Switch Unit. I was able to easily get the
Tuner Unit out (after finding those threads) and pull the Tuner Unit with
RL13 out of the loop and found that the relay RL201 which switches the tuner
out on Receive worked on one side and not the other.

So, hopefully replacing that relay will do the trick!

FYI

Mark

Mark

Tnx for the update. That's good news; sounds like the fix may not be
too painful/scary. I've really enjoyed my '765 over the years and given
the prices of most new rigs, will continue to do so! I've been out of
hf for a time but am stringing a high dipole this week. Looking forward
to bringing this 765 back to life. See you out there..

Gary

ICOM IC-765 Receive Sensitivty - DEAD
 

Yeah, that is what scares me! :-) I am calling Icom first thing tomorrow
(Monday). I know it was still available up to a couple of year's ago (from
one of the posts on Yahoo Groups). If they do have them, and they're not
too expensive, I am going to order a couple of them. I actually have
located the relay on the Antenna Switch Unit already. I have a part # too.
So, if I can just get my hands on it! :-)

ICOM IC-765 Receive Sensitivty - DEAD
 

Mark Bailey wrote:
Yeah, that is what scares me! :-) I am calling Icom first thing tomorrow
(Monday). I know it was still available up to a couple of year's ago (from
one of the posts on Yahoo Groups). If they do have them, and they're not
too expensive, I am going to order a couple of them. I actually have
located the relay on the Antenna Switch Unit already. I have a part # too.
So, if I can just get my hands on it! :-)

Mark,

Never really contemplated putting my hands on tuff-to-get specific
replacement components before. Hope they have one for you.

Gary

ICOM IC-765 Receive Sensitivty - DEAD
 

Well, ICOM had the RL201 part. She said they only show using 6 per year.
:-) Must be a rare failure. They stock lots of the RL13's, though. Go
figure. FWIW, they were prompt to get to me and get me squared away. Very
pleasant and refreshing.