[Elecraft] K3 erratic power output

[k7ca at infowest.com]

Hello All,
  I just received K3 kit serial # 1253 with KPA3, KBPF3, KXV3 and 
KUSB options.  The kit was very well thought out and was a pleasure 
to assemble.  It went together in under 8 hours.  Everything 
seemed to calibrate well and work perfectly except for the 100 watt 
PA.  When running 12 watts or less (8 watts on 6m) output is good and 
 stable.  When power is set higher which causes the 100 W PA to turn 
on, output power is not stable.  On 20m thru 6m with key down the  
power output takes about 6 or 7 seconds to stablize.  For example, 
when the power control is set for 50 watts it first comes up to 35 
watts, then slowly goes up to 60 or 70 watts, then slowly comes down 
to 50 watts where is is stable.  It seems like the power control 
zero's in on the correct power but very slowly.  With CW it never 
gets there. This happens every time the key is opened and then closed 
 again.  On 40m the same thing happens but there is about a 3 second 
delay after key closure before any output is seen.  There is no power 
 output at all on 80m and 160m even though with less than 12 watts 
set on the power control there is normal power output. I haven't had 
the time to look into the schematic yet so thought I'd see if any of 
the list readers have had a similar experience or may have some idea 
of a good place to start.    Thanks, Al K7CA