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Author Topic: Kenwood TM-281 Repair  (Read 162 times)

N8XI

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Kenwood TM-281 Repair
« on: August 27, 2022, 06:16:06 AM »

Gang,

My Kenwood TM-281 2M XCVR hasn't been used in awhile and when I tried to use it a couple of days ago it would RCV OK but when I pressed the MIC it wouldn't transmit and the LCD Display went blank.
Anyone know what the problem may be or know of someone that could repair it?

Thanks
73, Rick - N8XI
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73,
Rick - N8XI

WA3SKN

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Re: Kenwood TM-281 Repair
« Reply #1 on: August 27, 2022, 06:34:08 AM »

Was this with a known good dummy load connected to the antenna jack?  Sounds like the radio was not getting the required power.  Can you measure the voltage and current drawn when transmitting?

-Mike.
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WA9AFM

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Re: Kenwood TM-281 Repair
« Reply #2 on: August 27, 2022, 07:21:36 AM »

Was this with a known good dummy load connected to the antenna jack?  Sounds like the radio was not getting the required power.  Can you measure the voltage and current drawn when transmitting?

-Mike.

Ditto.  Receive doesn't require much power.
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W3WN

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Re: Kenwood TM-281 Repair
« Reply #3 on: August 27, 2022, 03:27:42 PM »

Try a different mike.

I’m having a similar issue with th TM-271 in the car, and in my case, it appears to be an issue within the RJ-45 connector on the mike.
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K1SPD

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Re: Kenwood TM-281 Repair
« Reply #4 on: August 27, 2022, 03:35:35 PM »

My 281 was having the same issue in my truck.  Ended up being a grounding issue
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N8XI

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Re: Kenwood TM-281 Repair
« Reply #5 on: August 28, 2022, 06:08:01 AM »

Was this with a known good dummy load connected to the antenna jack?  Sounds like the radio was not getting the required power.  Can you measure the voltage and current drawn when transmitting?

-Mike.

Mike, WA3SKN

Yes, a commercial 50 Ohm dummy load rated at 50W.
I have an Astron RS-20M and Receive is 13.5V @ less than 1A
Transmit the Ammeter kick a bit, essentially zero current and Voltage stays at 13.5V

73, Rick 
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73,
Rick - N8XI

N8XI

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Re: Kenwood TM-281 Repair
« Reply #6 on: August 28, 2022, 07:21:04 AM »

Well I found this:
https://www.youtube.com/watch?v=LrciUD_e0a0

I held the power leads and nothing happened but moved a few inches and it went into transmit.

Ended up moving the power leads about 6 inches and all is well.
Except I couldn't hear the squelch tail from the repeater.
I had forgotten about the Dummy Load.

I guess that's why they call it a "Dummy" Load  ;D
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73,
Rick - N8XI
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