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FT-747 stuck transmitting in CW mode

Jan 16th 2013, 22:17

KN6HF

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
I am trying to get back on the air after a couple of years. My Yaesu FT-747GX works as it should in all but CW mode. When CW mode is selected, it will, not unkey/continuously transmits. The MOX switch does not appear to be stuck and operates as it should in other modes. There is no key or keyer attached. Has anyone else experienced this problem? CW is my preferred mode of communication. I would like to get this fixed and get back on the air! Any pointers in the right direction would be greatly appreciated.
Dave
Jan 17th 2013, 02:18

KB0HAE

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
Hi. Does this happen without a key plugged in? What happens if you plug in a key? Maybe the key jack is shorted...just a thought...
Jan 17th 2013, 03:07

WA0CBW

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
Is it really transmitting or is it just muting the receiver?

Bill
Jan 17th 2013, 03:13

KN6HF

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
Thanks for the reply, this happens with or without a key plugged in. Power up the rig, it powers up into 7 MHz LSB, change mode to CW and it immediately starts transmitting. No switches or key will stop it. I have to power it back down to get it to stop. Powers back up into 7 MHz LSB again. Hmmm.
Jan 17th 2013, 03:15

KN6HF

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
The transmit light is on and emits what sounds like a constant CW tone.
Jan 17th 2013, 13:22

WB1GCM

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
I have owned one of these; this may be a sign that there is a processor problem. I would try resetting the processor. This procedure will erase anything stored in a memory. To do this, you need to press and hold the V/M and F Buttons while turning the transceiver on.

One problem with this radio and many others that were made in that era (80's-90's): they are mostly not repairable, since many of the key parts are not available anymore. If the processor goes, the radio becomes a glorified doorstop.

Bob Allison
WB1GCM
ARRL Test Engineer
Jan 17th 2013, 19:07

KN6HF

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
Bob,
Thank you. I will give that a try this evening. Could you clarify for me which buttons? would the V/M button be the VFO>M and the F button the FAST button?
Thanks,
Dave
Jan 18th 2013, 13:47

WB1GCM

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
Yes.
Jan 18th 2013, 19:42

KN6HF

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
Well that does not seem to work (the reset). I appreciate all the reply's. It looks like I will have to tear into it and see if I can repair it. I may have to buy a new rig. The Kenwood TS-590S is looking pretty good right now....
Dave
May 4th 2013, 00:52

randallk

Joined: Mar 15th 2013, 18:00
Total Topics: 0
Total Posts: 0
I have a Alinco DX-77 that starts transmitting a series of Beeps as soon as the key plug is inserted into the jack. The key is open and closing the key does cause the usual beep. Anyone have ideas on this as well. I am totally new to CW and basically know little.

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