Kenwood: Mic Kenwood TM-V71

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KK4JUG

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I believe the microphone for my Kenwood TM-V71 may have given up the ghost. Is there an easy way to test to determine that it is, in fact, the microphone and not the radio? The mic will key up a repeater but there's no modulation.
 

bharvey2

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I have a number of radios (both TM-V71 and others) that use the same mic. I've never had one fail. Not saying they couldn't however. My first thought would be that the mic cord had failed. If you're comfortable making up cables you could find the schematic online and build your own for testing purposes. That being said, these mic and copies of them are pretty easy to come by.

If I were inclined to actually test one, I'd check the wiring diagram and use a DVM that can measure into the microvolt range and check for voltage output on the element leads while providing an audible source to the mic. The wiring diagrams are in the back of the manual for the TM-V71A. If you don't have yours anymore, you can find them online.
 

KK4JUG

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I may have misspoke. I meant the microphone assembly (to include the cord).

Anyway, it might be less trouble for me to buy a mic than to make up a cable. My shop is more set up for woodworking than electronics.

I've learned that one wire line in the mic cable is shielded. That one line (from pin 6) apparently carries a clock signal from radio to the DTMF generator in the mic. The shielding prevents that clock signal from interfering with everything else.
 

bharvey2

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If you aren't set up for it, then getting a replacement is the way to go. I suspect you'll find they're fairly inexpensive. As far as the shielded conductors, you're right. I made up my own mic extension cable and fought with going without the shield. I kept getting noise during transmissions.
 

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I've learned that one wire line in the mic cable is shielded. That one line (from pin 6) apparently carries a clock signal from radio to the DTMF generator in the mic. The shielding prevents that clock signal from interfering with everything else.
Close, but not quite.

The mic audio is carried on pin 6. In the OEM Kenwood cables, it is shielded from the other wires in the cable. One of those other wires carries the clock signal.
 

KK4JUG

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What are the odds that it's the radio itself and not the mic/cord?

I'm guessin' the odds are pretty low but I'd rather hear it from someone who knows what they're talking about.
 

W9BU

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Take a good look at the mic jack on the radio. Make sure that the contacts are straight and lined up with each other. You might also try cleaning the contacts. Use isopropyl alcohol and a lint-free cloth.
 

FKimble

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You can call up Kenwood and order just the cable. It simply plugs into the radio and to the mic. If that fixes it great. Other wise you will have a spare cable for when it does go bad. Or it you have an ethernet cable laying around, you can use it to test. Due to the shielding needs, it audio won't be perfect, but it will tell you if the original cable is bad.

Frank KK4YTM
 

KK4JUG

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Thanks, Frank. I'm gonna hook up an Ethernet cable. I'm sure it will have some noise if it works but it'll also answer some questions.

W9BU, I'm gonna clean the contacts, too.
 
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KK4JUG

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I did all the testing and it turned out to be the microphone. I was able to buy the mic and cable for only a few cents more than just the mic alone. I ordered it from Giga Parts and it should arrive tomorrow.
 

bharvey2

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Glad to hear you got it fixed. Good choice in vendors too. I've purchased a couple of V71As from them (as well as other items) and have always been happy with their prices and customer service.
 

KK4JUG

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Love their prices but their shipping leaves a little to be desired. According to the USPS web site, GP created the shipping label for the mic on Friday, the 10th. It wasn't delivered to the post office until Monday, the 13th, however. It's supposed to arrive tomorrow. They're located in an adjacent state and it shouldn't take 5 days to get it here.
 

bharvey2

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Love their prices but their shipping leaves a little to be desired. According to the USPS web site, GP created the shipping label for the mic on Friday, the 10th. It wasn't delivered to the post office until Monday, the 13th, however. It's supposed to arrive tomorrow. They're located in an adjacent state and it shouldn't take 5 days to get it here.
That is strange. I'm in California and have normally received orders from them in less time than that.
 

KK4JUG

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I'm guessing it was late Friday, someone pulled the mic off the shelf, packaged it and created the mailing label. The "It's 5:00 o'clock and I've got a cold adult beverage waiting for me" bell goes off so the package sat on the table until Monday morning. It was Friday and I sort of understand. Had it been any other day of the week, I'd be more upset.

That may not be the best way to do business but it's the way many businesses operate That's OK, I'll still do business with them. It was what one of my friends would say is a "transitional anomaly."
 

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That's why I like doing business with DX Engineering whenever possible. If the item you order is in stock and you place the order before 8:00 pm Eastern time (I think it's 8pm), your order will be on a truck that evening.

I've noticed that lots of places print shipping labels one day, but the shipment doesn't show up with the carrier until the next day. Not sure if the delay is at the shipper or the carrier.
 

KK4JUG

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I think it's the shipper. The labels are created online and the packages are piled up in the corner and taken to the post office when they have time or the stack starts getting in the way, The post office's tracking system is the shipper's enemy in one respect because it shows how quickly the packages are physically taken to the post office and sent on their way.
 

bharvey2

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I'm guessing it was late Friday, someone pulled the mic off the shelf, packaged it and created the mailing label. The "It's 5:00 o'clock and I've got a cold adult beverage waiting for me" bell goes off so the package sat on the table until Monday morning. It was Friday and I sort of understand. Had it been any other day of the week, I'd be more upset.

That may not be the best way to do business but it's the way many businesses operate That's OK, I'll still do business with them. It was what one of my friends would say is a "transitional anomaly."
I suspect you've zeroed in on the problem. I find that stuff happens in direct proportion to my level of need and anticipation. I'ts truly uncanny.
 

KK4JUG

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OK, guys, I told you no hard feelings on Gigaparts because of the slow shipping. Well, yesterday, I ordered a complete system from them. I ordered a quad-band radio (Yaesu FT-8900R), antenna, coax, mount and programming software. I wasn't sure the coax assembly and mount would be compatible so I took advantage of their online chat system. They assured me everything would work. On a whim, I asked if I would get a discount for ordering a complete system. Not a chance, he said, but he came back with $10.00 off if I used a certain discount code at checkout. I tried that and the computer said it was invalid.

I realize that in the grand scheme of things (almost $550.00 in this case), $10.00 isn't much but it's another little red flag about their customer service to go along with their "molasses in January" shipping screw-up earlier. The stuff I ordered is coming from at least two different places so let's see what happens.
 
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