[Kenwood] TS-850 no power

[Dennis Bombardiere]

After about 3 hours Saturday my 850 stopped transmitting.  At first I noticed intermittent no alc during a sentence.  Then no audio output, but I did have full power on CW.  Next there was no power output on CW.  After it cools down I have full power (100 watts) on CW for about 15 seconds and then no power output.
     I will appreciate any help or ideas.  73  
                                                        Dennis W8YS