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Post by publius on Sept 9, 2011 13:37:33 GMT -5
I have this problem with the FT 747GX .Although when testing with the dummy load the Tx -CW and SSB- the transceiver works perfect ,when I change to SSB to transmit and press the PTT,the meter of the set goes to maximum without modulation.I checked the antenna ,coaxial cable and connections and found that there is no fault.I noticed that the TX connection at the back is becomming a little hot.Can anyone suggest any solution or perhaps inform me of the fault.Thanks
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Post by danfinn on Sept 11, 2011 19:52:30 GMT -5
I purchased my ft-747gxe in 1991 (new). By 1996, I started having the same problem. It tested fine with a dummy load but would not transmit with a real antenna. I sent it to Yaesu and the Yaesu tech service in Calf kept saying it was OK. I kept telling them it was ok only with a resistive dummy load but not with a real antenna connected to it. Finally after sending back and forth 3 times from NC they actually tested with a real antenna which is a reactive load. They had to replace the transistors in the power amplifier which apparently had been damaged due to (my) previous abuse of running a long wire antenna and tuning at high power. There is a difference between transmitting into resistive dummy loads and reactive antenna loads and the output stage is susceptible to this kind of damage where it cannot handle even a slight reactive antenna load. With the rebuilt PA it is now 2011 and I have had no problems since.
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Post by publius on Sept 12, 2011 9:05:27 GMT -5
to danfinn,
Thanks for your reply
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