[K4RY] K4RY: HF Transceiver Failure

[WB4LNM at aol.com]

This morning, the Kenwood TS-450S transceiver in the K4RY shack  failed 
shortly after it was powered up.  The first indication that  something was not 
right was a low tone modulation on all received signals that  caused them to 
be very difficult to understand.  
 
Soon afterwards, the transceiver sent a couple of Morse code letter groups  
"UL", the display went to just showing decimal points, and audio output  
vanished.  Perhaps related, but in an unknown fashion, the automatic  antenna 
tuner was making unusual sounds.  These symptoms were seen  by Jimmy and me. 
 
 
This evening, I looked at the service manual for the radio, and the  
all-decimal point display is a sign that one or more of the PLL's has become  
unlocked.  This perhaps would have caused the modulation on the received  audio 
prior to unlocking.  Additionally, if the root cause is something  like an 
internal voltage supply regulator going bad, that could have caused the  
unusual noises in the tuner as well.  I will not have time to look at it  for 
the next two weeks, but perhaps after that.  If anyone else can  volunteer to 
examine the radio, I'll be glad to loan them the service  manual.  Drop me 
an email here.  
 
Since we have the School Club Roundup starting next Monday, I will attempt  
to bring in my Yaesu FT-757 with automatic antenna tuner on Sunday sometime 
 and get it set up for operation.  I would appreciate if you would again  
look at your calendars for next week and let me know when you might have an 
hour  or two for operation.  
 
73
 
John...
WB4LNM
 
 
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