[ICOM] IC-756PROIII No Transmit ESD Failures

[ALAN ZACK]

I reported previously to the reflector on my problems with my IC-756PROIII
that Icom blamed on ESD. From the reflector I learned there are many more
people experiencing  the same problem.

 

This rig was purchased in November 2008 was returned to ICOM in March 2009
for warranty service with no transmit, no power out in any mode. ICOM
replaced the following parts. Part numbers are 1110006430, 1750000581,
1750000851, and 1530003091. They only listed 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, the repaired
rig just turned up when a FedEx driver rang my door bell. I was later told
they are the T/R switching diodes on the control board.

 

It went back at ICOM for a different problem in July 2009. I turned 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 was some sort of harmonic oscillation.

 

I received a call from Icom asking how I wished to pay $213.00 for that
repair. I told them it should be under warranty but was told the failure was
again caused by ESD and not covered by the warranty. This was a different
failure than the first. 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. The DTS-4 has a 12 volt sense line. When the station
is shut down and 12 volts is removed from the DTS-4 it puts all antenna
connections to ground. I double checked the action using an ohmmeter and
sure enough all four antenna connections are grounded when I shut off the
rig. I have ICE model 300U 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 all failures, it was the
transmit function that failed with separate problems. I live in Las Vegas.
We don't have much 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. This is
the only rig on the air. There are no other transmitters nearby to feed RF
to the IC-756PROIII. All these failures occurred when the rig was off and
the antenna connections were grounded by the DTS-4. At all times the rig was
working fine, turned off, then when later turned on there was the failure.
These are not on the air failures.

 

On the last repair in August 2009 I did receive a return call from the Icom
tech who did the repairs. The first phone call 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 was told that was again the same T/R switching diodes on the
control board that failed supposedly from ESD even though the actual failure
was different. 

 

The Icom tech told 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.

 

Now the rig is out of warranty and I will contact Icom and ask if they will
cover the repair. I doubt they will as they did not want to cover the second
repair while it was still under warranty. This really seems to be a design
failure such as was in the IC-746PRO. Icom accepted responsibility and
repaired those affected units free of charge even if they were out of
warranty. I believe Icom should do the same for this supposed ESD failure of
the 756PROIII.

 

Burghardt Radio Repair Inc has a module which they have produced called the
BEV-756 ($79.95 plus labor) which they claim does protect against that exact
problem.   They state it is very effective and have had no failures after
the install of over 400 modules. Their approximate labor for repair and
install would be $187.50.  If Burghardt can come up with a fix then why not
Icom?

Has anyone else come up with a solution to this ESD problem? Is there a
lemon law to protect against this repeated failure?

 

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 with no problems while the 756
is again broken.

 

I was about to trade up to a IC-7600 but am not happy with these supposed
ESD failures on Icom rigs. First it was the 746PRO, now the 756PROIII. If I
am going to invest $4,000 in a new rig I don't want any more failures. How
many Toyotas are being sold right now? Pay attention Icom.

 

_______________________________________________________

 

 

 

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

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