[ICOM] IC-756PROIII No Transmit

Fri Jul 17 11:25:40 EDT 2009

Hello Alan!
The same problems as I have had several times.
Never had any problems with my 765.
73 de Ken / SM7CQY

Den 09-07-16 23.40, skrev "Alan Zack" <k7acz at cox.net>:

> My 756ProIII is back at the Icom America Bellevue Service Center for the
> second time. This rig was purchased in November 2008 and should still be
> in warranty.
> It was returned to ICOM in March 2009 for no transmit, no power out in
> any mode. ICOM replaced the following parts. They only list the part
> numbers, not the actual devices so I can't be sure what exactly was
> replaced. There were no notes, no repair description or phone calls
> about the problem, it just turned up when a FedEx driver rang my door
> bell. Part numbers are 1110006430, 1750000581, 1750000851,and
> 1530003091. I was later told they are the T/R switching diodes on the
> control board.
> 
> Now it is back at ICOM for a different problem. The rig was on, I saw a
> spot for someone I wanted to call, and when I keyed the mic (SSB) I had
> a steady carrier at more than the normal 100 watts output. I tried all
> bands and modes. With no CW key or mic connected, no matter what
> mode/band was selected, the rig put out a 100 watt plus carrier. I am
> assuming it is some sort of harmonic oscillation.
> 
> I received a call from Icom asking how I wished to pay $213.00 for the
> current repairs. I told them it should be under warranty but was told
> the failure was caused by ESD and not covered by the warranty. They said
> they would get back to me.
> 
> I only have one antenna connection to the rig from a LDG model DTS-4
> antenna switch. There is a Force 12 beam at 55 ft, a sloper, and a
> vertical connected to the DTS-4. When I shut off the rig I also set the
> DTS-4 to GROUND ALL which grounds the antenna jacks. I also turn off the
> power supply. I have PolyPhaser coaxial protectors on all coaxes where
> they enter the house, grounded to a ground rod professionally installed
> by the company that installed my tower. With all my antennas grounded
> and the P.S. turned off how would I get ESD to the rig? Also, ESD to me
> is what happens to your receiver front end. The receiver worked FB on
> both failures, it was the transmit function that failed with two
> separate problems. I live in Las Vegas. We don't have rain or
> thunderstorms here. I do realize there can be static in the air, that's
> why the USCG C-130's I flew in and worked on had static discharge wicks
> on the trailing edge of the wings but I don't think I have that kind of
> static in the air to effect a stationary antenna at 55 ft. There are no
> transverters, CVI devices, etc, connected to the rig.
> 
> I have now received a return call from the Icom tech who is doing the
> repairs. The first phone I received was from the billing department and
> they were not able to provide me with the technical reasons why they
> believe my failure is due to ESD and not covered by warranty. I am told
> that is again the same T/R switching diodes on the control board that
> failed supposedly from ESD. It seems I better check the grounding
> operation of my DTS-4 ant switching box and outside ground connections.
> I was told that just disconnecting the ant from the rig is not good
> enough, that the static charge can stay in the coax (capacitor effect)
> and then you reconnect the coax to the rig you will destroy these
> diodes. The coax must be grounded while disconnected. The Icom tech
> tells me he sees a lot of these failures from dry states such as mine,
> NV, as well as AZ, NM, UT, etc. where there can be dry static in the air
> without a storm. So what are you supposed to do? I am a contester. I
> can't have my ant coax grounded while I am in a 48 hour contest. If Icom
> is seeing these T/R diode failures even when there are no thunderstorms
> then I think they should do something to better protect them.
> 
> BTW, I used a IC-746 (non PRO) for years and years and never had a
> problem. I am now using the IC-746 as my back up rig while the 756 is at
> Icom with no problems.
> 
> _______________________________________________________
> Alan Zack
> Amateur Radio Station K7ACZ
> Official USCG Auxiliary Comm Station
> Las Vegas, Nevada, USA
> Delta Rocket Quality Engineer, The Boeing Company, Retired
> Aviation Chief Warrant Officer,  U.S. Coast Guard, Retired
> ---------------------------------------------------------------------
> 
> ----- Original Message -----
> From: <k0bx at arrl.net>
> To: "ICOM Reflector" <icom at mailman.qth.net>
> Sent: Tuesday, March 24, 2009 12:40 PM
> Subject: [ICOM] IC-756PROIII No Transmit
> 
> 
>> 
>> Larry, thank you for your comments.  I do agree with what you said.
>> 
>> But in my case, I do not have any other antenna connected.  The 1st
>> time was on 20 CW using my Hygain 204BA 4 element monobander with no
>> amp.  I agree that some RF must be getting back to the rig somehow,
>> but I do have grounding devices on all my antennas.
>> 
>> The 2nd time, I just (Like the other guy) just turned on the rig to
>> find it dead on transmit.  I know that sounds like an e-bay thing, "It
>> worked the last time I used it".
>> 
>> One of the gentlemen in my DX Club got rig of his PROIII after 3
>> repairs for the samething.
>> 
>> I have used a TS-850S on this antenna for 12 years and when taken out
>> of service it performed on transmit like the day it was brought.  My
>> IC-706MK2G have been on this antenna for the last 5 years.  No
>> problems with them.
>> 
>> As far as the Burghardt BEV-756, Burghardt recommended it as a
>> solution to my problem even though I do not use a Bev Antenna.
>> 
>> It seems that others are having the same problem and only using one
>> antenna at a time.
>> 
>> Joe K0BX
>> 
>> 
>> Stop the insanity!
>> Please do not add me to any distribution lists (Joke, Stories or Junk)
>> without my permission.
>> 
>> 
>> --- On Tue, 3/24/09, Lawrence Young <k4lxv at bellsouth.net> wrote:
>> 
>>> From: Lawrence Young <k4lxv at bellsouth.net>
>>> Subject: Re: [ICOM] IC-756PROIII No Transmit
>>> To: "ICOM Reflector" <icom at mailman.qth.net>
>>> Date: Tuesday, March 24, 2009, 9:03 AM
>>> Guys: Products like the Burghardt BEV-756 are designed to
>>> serve as a front end saver for those hams who may not
>>> understand that one cannot safely transmit on one antenna
>>> and leave another one such as a Beverage receive antenna
>>> still connected to the receiver. I am amazed at the number
>>> of hams that I know who may do this without realizing the
>>> possibility of damage to the radio.
>>> Larry K4LXV
>>> 
>> 
>> ----
>> Your Moderator: Dick Flanagan K7VC: icom-owner at mailman.qth.net
>> Icom Users Net: Sundays, 1700Z, 14.316 MHz
>> Icom FAQ: http://www.qsl.net/icom/
>> To support QSL/QTH.net: http://www.qsl.net/donate.html
>> 
> 
> ----
> Your Moderator: Dick Flanagan K7VC: icom-owner at mailman.qth.net
> Icom Users Net: Sundays, 1700Z, 14.316 MHz
> Icom FAQ: http://www.qsl.net/icom/
> To support QSL/QTH.net: http://www.qsl.net/donate.html