Kenwood: Used Kenwood TK-80 power issue

[wikusm]

Hi everyone, this is my first post here, I am a new HAM, I purchased a used Kenwood TK-80 HF transceiver from a guy over the weekend, he sent me videos of the radio working fine etc, now however once I got it home (and checking his videos) I noticed that no matter my power source, the radio will only transmit in Low power mode. The moment I switch to Mid, High or Max and key up, the radio cycles off/on again, first thought it might be an issue with the powered mic, so tried a morse key also, and does exactly the same. Took the radio to a fellow ham to check with his power supply and SWR meter in line, exact same issue. I am quite disappointed as this is my first HF radio, and now I don't even know where to start. The guy refuses to refund me, saying the radio worked 100%. Any tips on where to start? Just want to mention I had it running off a 13.6V 30A switch mode power supply, with an inverted V antenna and an auto antenna tuner. Really hope someone has come across a problem like this that could point me in the right direction Thanks in advance.

73
ZS1WLM

 

[mmckenna]

Usually that sort of issue is caused by voltage starvation. A power supply not providing enough current will cause the voltage to drop and the radio will restart.

Since you said you tried it with a 30 amp power supply, and that ~should~ run it fine, I'd start taking a close look at all your power connections. Faulty crimps, bad fuse connectors, loose connection will all cause issues like this.

If you can, also try hooking it up to a car battery and see if it still happens. 30amps should be enough to run it, but give it a try and see if it helps.