[ICOM] IC-756PROIII No Transmit

[Phil Krichbaum]

    When I first took my PROIII out of the box I made 2 short QRP cw 
QSOs on 20m and one short contest type exchange at 100w on 20 cw into a 
resonant antenna and power out went to zero an hour after I first turned 
it on. I sent it to Icom and initially they said I was using it in a non 
warranty use (that I couldn't understand) and charged me for the repair. 
After a few phone calls they refunded me the repair charge but I had to 
pay the shipping to them. (I'd previously had a PROII that was fried by 
lightening coming in the ground side of the power line and via the 
computer interface and cw plugs from the computer (computer HD also 
toasted) so I have a good amount of experience with using the 756PRO 
series). I've had two other instances after the warranty expired on the 
PROIII, one was probably from snow static. All problems seem to relate 
to problems with FETs and diodes in the tuner or possible strong signals 
coming in the transverter or RX antenna jack. I've never used the 
transverter jack and use a KD9SV DxPedition Model II receive antenna 
switch/preamp in line with the transmit antenna jack for my RX antennas 
which disconnects the RX antenna during transmit. In the most recent 
failure, when starting to transmit, power out was very QRP and went to 
full power after 2-5 seconds but not always as it was intermittent. Also 
the 12m toroid in the tuner toasted and put out a large amount of smoke. 
I should have it back from the latest repair soon.
    73 Phil N0KE

Alan Zack wrote:
> I turned on my IC-756PROIII this morning and found no transmit on any band. It has been working fine. When attempting to transmit on RTTY or CW there is no carrier, no power out shown on the Transceivers PO meter or an external meter. The red TX LED light comes on and the fan speeds up but no power out. On SSB there is no power out on voice peaks, no ALC readings but the COMP meter does show a small deflection on SSB on voice peaks. Receive is normal.
>
> I did the CPU reset with no help.
>
> I disconnected the 756PROIII from the power supply and antenna and connected my back up IC-746 to the same antenna and power supply connections. The IC-746 works FB telling me the power supply or antenna are not the problem.
>
> There is no computer interfaces, etc, involved. Just the basic power supply, antenna, and speaker connections.
>
> Does the 756PROIII suffer from the loss of power out problems that the IC-746PRO did?
>
> Any suggestions before I box it up and send it to Icom? It was ordered on Nov 26, 2008 and shipped on Dec 2, 2008 from HRO Anaheim so is still under warranty.
> _______________________________________________________
> Alan Zack
> Amateur Radio Station K7ACZ
> 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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