Kenwood: TM271A

[Polarbear837]

I am having issues with my Kenwood TM271A. Every time I key up the radio, it turns its self off. When I
un-key, it comes back on. Any suggestions?

 

[bryan_herbert]

What are you using to power the radio? This usually happens when insufficient current is applied.

 

[Polarbear837]

Its hooked up to my vehicle. I have it connected to a fuse box which is supplied by the truck battery

 

[bharvey2]

This sounds like a power problem. As I recall, the 271 is a fairly high powered radio so you'll need heavy power conductors (I'd use no less than #10 AWG), and run the positive lead directly to the battery (fused at the battery of course) I'd run the negative to the battery too but some people will ground it to the vehicle chassis. Doing the latter to a poorly grounded piece of metal will likely cause a voltage drop and cause the symptom you are describing. So too will using wire/conductors that are too small. Poor connections are sources of problems as well. Just as a test you might reduce your output power to the lowest setting and see if you still have the problem. The problem may not occur on low power.

 

[chief21]

I agree that this is most likely an insufficient power/current problem. If the rig continues to work on low power TX but not on high, that would clearly point to a power issue.

I've also read that problems can sometimes develop with the Kenwood fuse holders. Make sure that all connections within the fuse holders are mechanically solid and not corroded. Good luck.

John

 

[robertmac]

Isn't this radio an amateur transceiver? Is he trying to transmit out of band and could be getting a lousy match? I would expect an licensed amateur radio operator to know what is causing this problem.

 

[Skypilot007]

Isn't this radio an amateur transceiver? Is he trying to transmit out of band and could be getting a lousy match? I would expect an licensed amateur radio operator to know what is causing this problem.

My thoughts exactly. Anyone with a tech ticket should be able to figure this out. :roll:

 

[bharvey2]

Isn't this radio an amateur transceiver? Is he trying to transmit out of band and could be getting a lousy match? I would expect an licensed amateur radio operator to know what is causing this problem.

Did the OP post in another thread? I don't see anything about what frequency he's transmitting on.

 

[jdifabio]

Hello, I had a similar issue with my TM281A, it was an inadequate power supply. Hope this helps. Joe

 

[mikewazowski]

Moved to Amateur Radio Equipment forum.

 

[Polarbear837]

If you don't have any advise, don't post

 

[robertmac]

But we did. But a lot more information is required. As some and I have said, what power, what frequency, what amps rating have you hooked it up to, what is the swr, and perhaps type of coax and antenna. All things an amateur radio operator should know. And would need to know to give a half decent answer.

 

[Polarbear837]

Have you ever forgot anything? I'm handicapped and I tend to forget things I just ask a question for help and I get jumped on for not knowing a simple thing.

 

[ShawnInPaso]

Hey Polarbear -

The cause of the problem is most likely caused by the lack of DC current getting to the radio as other have said (could be SWR related, but it would not be the most likely issue). If you haven't already done so, check to be sure the radio is on "low" power. As you know, those rigs put out 25 watts or more on low power and as much as 60 watts on high power, a real current sucker.

Sometimes the lack of DC current issue isn't quite as obvious as some may consider. Here are some steps you can take to determine where the problem is (could be one or more involved):

1. Connect the power leads, at least temporarily, directly to the battery terminals. Be sure there is a fuse between the radio and the battery (I know the TM271A has a fuse in line but just not making any assumptions). Check the radio on low, then high power to see if it works.

2. If the radio doesn't work after the first test, remove the inline fuse, clean the fuse holder and insert a new fuse. Try the radio again to see if it works.

3. If the 1st and 2nd test don't work, check and inspect the DC power connector on the radio. It doesn't take much for the wires to come loose inside of the connector something that may not be detected by just looking at it. Try wiggling the wire as it goes into the connector as you transmit to determine if a loose wire might be the issue. Better yet, if you have a VOM, use it to determine if there is continuity from one end of each wire to the female end of the power connector.

I'd say that if none of these three steps identify the problem then it's something other than a DC current issue. Could be really bad SWR shutting down the rig, or something else internal to the radio that's bad.

As an aside, I have a couple of TM271A rigs, so please feel free to PM me if I can be of any help.

Best,

 

[robertmac]

Have you ever forgot anything? I'm handicapped and I tend to forget things I just ask a question for help and I get jumped on for not knowing a simple thing.

There are a lot of people that forget. There are a lot that are handicapped. That doesn't make it right to use an amateur radio on a frequency it isn't intended to be used. If you are trying to use it on an amateur radio frequency, and are licensed, than what frequency? What power level are you using, what is the power rating of the fuse you have it hooked to, have you measured the swr? To continue, what coax are you using, what antenna and how is it attached to vehicle. We are not mind readers and as you can see, hopefully, there is no simple answer if one does not know the facts. Far too many people post in these threads expecting a definitive answer from a question lacking the needed information. People are offering solutions but you don't respond to their requests. There is often more than one problem with your situation but you are just ignoring requests for which you should be able to answer. We can continue with you answering: frequency transmitting on, power level, fuse/power rating, coax, antenna, mounting system including any grounding used, swr.

 

[robertmac]

Did the OP post in another thread? I don't see anything about what frequency he's transmitting on.

Yes it was originally posted in the Kenwood commercial thread. I did notice another thread today that he posted a few years ago involving programming a commercial Kenwood transceiver. There was no posting stating problem had been solved. I just hope he provides more information on how this amateur radio is connected other than to fuse box.

 

[bharvey2]

Yes it was originally posted in the Kenwood commercial thread. I did notice another thread today that he posted a few years ago involving programming a commercial Kenwood transceiver. There was no posting stating problem had been solved. I just hope he provides more information on how this amateur radio is connected other than to fuse box.

Ah, that explains it. Good catch....and your right, incomplete information posed in a question could lead to some bad (albeit well intentioned) responses. Everyone ends up chasing rabbits down rabbit holes.

 

[Polarbear837]

Thanks for all the advise. I got it figured out and the radio is up and running

 

[Hans13]

Thanks for all the advise. I got it figured out and the radio is up and running

So, what was the problem and solution? By posting the resolution, you may help someone else in the future searching for answers to a similar problem.

 

[K5MPH]

Sound like you are not getting the right voltage to the radio try connecting it direct to the Battery....