[PJL]

Now I am in trouble! I am looking at the 2nd local oscillator buffers (AA7 page 213) that drives the mixer (AZ1 on AC1) that takes off 36.4MHz to make the 200MHz signal for the counter/tracking generator. This is the signal that appears to be low.

The circuit is attached and what I am seeing is the output marked AZ2 on AB9 , also a balanced mixer, is almost twice the amplitude. I can see that the common base TR8 is going to attenuate the signal but I would have thought that any loss would be recovered by TR9 but I guess it would all depend on the loading? I also note that R20 is 270 ohms but it has a mark by it and I wonder if that means adjust to obtain required output level?

So based on this it would seem there is a problem with the TR8/TR9 buffer stages or the loading from the AZ1 balance mixer. I need to search through the manual to see if there is any mention of the amplitude of the AZ2/AB9 output.