Kenwood TM-V708A TX Issue

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jmp883

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I've had a Kenwood TM-V708A radio in my truck for a few years now and have never had an issue with its operation. Today, during a QSO it stopped transmitting audio. The meter still showed that the radio was transmitting a signal but there was no audio and I wasn't able to activate the courtesy tones on my local repeater. I pulled off the road, checked all the power and antenna connections (they were all fine, tight, and secure) and then called the person I was talking with on the air via cellphone. The first 2 times I tested the radio again it was showing a signal going out on the meter but he was not able to hear me on-air at all. The 3rd (and final time) we tested it he caught about half my callsign before my radio apparently stopped sending the audio again.

The fan activates every time I key up so I don't think it's an overheating issue and the meter shows signal going out each time, it just doesn't seem to be sending the audio. It receives just fine so I'm not worried about that side of the radio. I'm wondering if it's either the finals going bad, or more hopefully, the microphone going bad. Since he has the same radio we're going to swap microphones tomorrow to see what happens there.

If anyone has thoughts, ideas, or previous experience with this type of problem I'd appreciate hearing from you.

Thanking you all in advance!
 

kayn1n32008

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... Today, during a QSO it stopped transmitting audio. The meter still showed that the radio was transmitting a signal but there was no audio and I wasn't able to activate the courtesy tones on my local repeater... The first 2 times I tested the radio again it was showing a signal going out on the meter but he was not able to hear me on-air at all. The 3rd (and final time) we tested it he caught about half my callsign before my radio apparently stopped sending the audio again...

Thanking you all in advance!

High SWR posssibly. Or over temp. protection could be another.
 

fineshot1

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Joined
Sep 17, 2004
Messages
2,479
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NJ USA (Republic of NJ)
I've had a Kenwood TM-V708A radio in my truck for a few years now and have never had an issue with its operation. Today, during a QSO it stopped transmitting audio. The meter still showed that the radio was transmitting a signal but there was no audio and I wasn't able to activate the courtesy tones on my local repeater. I pulled off the road, checked all the power and antenna connections (they were all fine, tight, and secure) and then called the person I was talking with on the air via cellphone. The first 2 times I tested the radio again it was showing a signal going out on the meter but he was not able to hear me on-air at all. The 3rd (and final time) we tested it he caught about half my callsign before my radio apparently stopped sending the audio again.

The fan activates every time I key up so I don't think it's an overheating issue and the meter shows signal going out each time, it just doesn't seem to be sending the audio. It receives just fine so I'm not worried about that side of the radio. I'm wondering if it's either the finals going bad, or more hopefully, the microphone going bad. Since he has the same radio we're going to swap microphones tomorrow to see what happens there.

If anyone has thoughts, ideas, or previous experience with this type of problem I'd appreciate hearing from you.

Thanking you all in advance!
It could be a lot of things so it should be checked with at least a power out/swr meter
and verfied to have full power out. If so, the antenna swr needs to be checked and or
the antenna connection. Doesn't sound like its a mike audio problem otherwise you would
at least still be keying up the repeater and getting back a coutesy tone but check it anyway.
 

jmp883

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Joined
Jan 7, 2005
Messages
590
Location
Northern NJ
Thanks for all your replies.

It looks like I'll be taking the Kenwood out of the truck for now and re-installing one of my Yaesu FT-7800's. It basically did the same thing again today so it's time to take things to the next level. All antenna, power, and microphone connections are tight and solid. I also swapped microphones with my friends Kenwood and everything worked ok during our test.

I was looking to upgrade to an APRS-capable radio.....but not until later this year!

Thanks again guys :D
 
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