Question about Kenwood FreeTalk XL TK-3101 (15 Channels) 2-Way Radio

Kenwood TK 3101 two way radio problem

I have 2 radio's that were power backwards. What I mean is they were hooked up to a car power adapter. The problem was the wires in the cigarette lighter were reversed. Before both worked great, afterwards both would not power up. I an hoping there is a internal fuse or something cheap to fix. Can you help?? Thanks Smitty

smitty141 Jul 06, 2008

Thanks Freetek, It was simply my poor judgment. I use these radios as
a bike to bike (motorcycle) communications. I use a Autocom battery
adapter that hooks to bike power. Were I went wrong I was connecting
power to a tank bag. I reversed the wires on "power out" and plugged
the first radio in. It did not work, and like a dummy I grabbed my
spare and you can guess what happen next. In the end, two bad radio's.
Thanks Smitty

1 Answer

Steve Allison

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5,569 Answers

Most devices that can be operated from external supplies have a diode across the the power jack that will short the source if the polarity is reversed.
Since this is a pretty small part without much chance of surviving the current available from a cigarette lighter socket, the only hope you have is that the fuse almost always found in these 'adaptors' will blow before the diode fails.

If the radios will not operate from batteries, I'm afraid they are badly damaged.

It son't hurt much now if you open the case and check near the power jack for burned parts. The diode(s) probably aren't there at all any more since they are commonly capable of no more than an amp or two and the typical fuse in those car adaptors is 5-10 amps, enough current to cause the diode to explode before the fuse blows.

I don't know where you reside, but in the US there are many sources for low-cost digital multimeters (<$20 US) that would have prevented your problem simply by checking the polarity of the jack before plugging it in.
I don't think the lighter was at fault; I believe the adaptor was wired for a particular item, just not for your radios.
It's always chancy to use a power source only because the plugs match.

Most devices have a small symbol molded into the plastic near the power jack showing which polarity input is correct.

Posted on Jul 05, 2008