[Elecraft] Question about K2's Q7 and Q8 Final Amp

[redmen1969 at optonline.net]

Hi,

  My K2 has been working fine but I decided to fix it anyway...hi.

  Well actually I was a little short on the power output on 10 meters.  I was getting about 7 watts out on 10 meters and Gary Suggested that I replace T2 and T1.  Instead of winding them myself, I contacted 'The Toroid Guy' and he sent me two beauties (along with a T-4) - the guy is great, BTW.

  So yesterday I installed the new T1 and T2 (I did not yet install T4) and replaced the heat sink.  The K2 manual warns that whenever the heat sink is removed and replaced you should verify that the collectors of Q7 and Q8 are not shorted to ground.

  With the heatsink attached I check and sure enough, there was a short between the collector (middle pin) and ground (the ground wire on the RF board) - I used the continuity buzzer on my DMM for this.

  I removed the heatsink and all of the hardware which connects Q7 and Q8 to the heatsink and then again checked for the sort.  It was still there.

  In looking at the schematic, the section of the final which contains Q7 and Q8 seems pretty isolated from everything else, with just T3 and T4 seemingly getting into the action.  Try as a I might I couldn't locate any shorts.  Using the schematic, I started at the collectors of the transistors and worked to the right of the schematic.

  The only options I have presently connected are the Noise Blanker and the SSB module, both of which don't seem to be involved with the finals.

  Obviously the problem must be in the area that I was working on.  

If anyone has any suggestions in tracking this down, I appreciate your help

Tom, WB2QDG
K2 1103