Kenwood TS-450SAT

[kitster007]

I recently purchased this radio and it has a TX problem. It seems when the rig is cold it works and modulates to a full 100 watts @ 13.85 Volts with power and modulation at 100%. Once the unit warms up then it will only put out 1/2 watt output but still receives fine. If I turn unit off and let it get cold then turn back on same symptom. I was wondering if anyone out there has seen this problem before? I took all the panels off and everything in this rig looks clean around the transmit finals and the capacitors look clean. I was kinda leaning towards maybe a bad thermostat or regulator? All the testing so far has been on 10 meters. If anyone can help me out with troubleshooting or lead me to a technician that maybe has seen this issue. Any help would be greatly appreciated.

 

[Wiskey Delta-40]

If someone can not help you here try Clif@AVVID in texas..

Did a good job on my TS 790A

 

[wavrider]

More info.

Is this in CW mode or SSB?

Does the internal fan come on?

Have you tried putting a small exterior fan blowing on the back of the rig to try and keep it cooler?

Are you testing it into a dummy load or an antenna?

What is the VSWR of the antenna on the frequency you are testing it at?

I recently purchased this radio and it has a TX problem. It seems when the rig is cold it works and modulates to a full 100 watts @ 13.85 Volts with power and modulation at 100%. Once the unit warms up then it will only put out 1/2 watt output but still receives fine. If I turn unit off and let it get cold then turn back on same symptom. I was wondering if anyone out there has seen this problem before? I took all the panels off and everything in this rig looks clean around the transmit finals and the capacitors look clean. I was kinda leaning towards maybe a bad thermostat or regulator? All the testing so far has been on 10 meters. If anyone can help me out with troubleshooting or lead me to a technician that maybe has seen this issue. Any help would be greatly appreciated.

 

[kitster007]

More info.

Is this in CW mode or SSB?

Does the internal fan come on?

Have you tried putting a small exterior fan blowing on the back of the rig to try and keep it cooler?

Are you testing it into a dummy load or an antenna?

What is the VSWR of the antenna on the frequency you are testing it at?

I was testing on SSB and yes the internal fan spins on keydown. I was testing on an antenna with a SWR of around 1.5 to 1.8 to 1 on 28000mhz. Haven't tried to bypass the Antenna tuner to verify its working correctly thou.

 

[wavrider]

Try to test without the tuner. Dummy load would be great for testing all bands.