TK-705 Changes Channels On Its Own

henryg · Post by **henryg** » Thu May 17, 2007 9:47 am

Hello. I have a TK-705 installed in a Chevy Astro Van. Occasionally when the van is started, the radio will be on CH 16, not on CH 1 where it was left. I thought it was a programing issue, reprogramed, no change. I swapped out the radio and it did it again. Any ideas? Thank you. Henry

n5tbu · Post by **n5tbu** » Thu May 17, 2007 10:34 am

Do you have it wired to go on and off with the key?
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henryg · Post by **henryg** » Thu May 17, 2007 12:05 pm

Yes, it is wired to the ignition.

n5tbu · Post by **n5tbu** » Thu May 17, 2007 12:21 pm

When starting your Astro the radio is seeing some strange voltages.
I suggest you wire to the battery and use the radio's on/off button
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ka7wnf · Post by **ka7wnf** » Thu May 17, 2007 3:25 pm

Mine does the same thing. So I reprogrammed it so the channel I use most is now on 16. It doesn't seem to like the voltages on engine start.

n5tbu · Post by **n5tbu** » Thu May 17, 2007 3:38 pm

Maybe using a relay wired to be on with Ign and the normally open contacs to make/break the power coming from the battery would solve the prob.
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ka7wnf · Post by **ka7wnf** » Thu May 17, 2007 4:51 pm

Or some sort of delayed relay that waits a second or 2 before closing after the engine is started. But it could be just turning on the radio. I wonder if units used as base stations do this..

n5tbu · Post by **n5tbu** » Thu May 17, 2007 9:14 pm

I think the problem is that the radio sits at low voltage long enough to confuse the microP it never gets it's reset command and sits in limbo.
Yes a delay relay would fix this.....but still,how hard is it o get used to turn on the radio after you get mobile??! a much easier solution!
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ka7wnf · Post by **ka7wnf** » Fri May 18, 2007 9:13 am

Turning it on is easy to remember. Remembering to turn it off and needing to jump start the truck 3 days later is yet another