I measured that on the control pin U5 is 0V if it works as Spectrum Analyzer. And if it works as a generator, there are 3V on the control pin regardless of whether we work in Cleanest Signal or Highest Accuracy mode. From U6, the 1.5GHz signal on pin 4 only comes out in cleanest signal mode.?
It seems to me that U5 switches the signal for U6 transmit/receive and rather this works correctly. Next to U5 is U29, which, regardless of the mode, is always controlled by a high 3V state, which directs the signal to U7. Under what conditions should the signal controlling U29 switch to 0V? The other output of U29 goes to R46 R3 R48 which looks like a attenuator and goes somewhere on the other side of the PCB. The output of R48 looks like it is shorted to ground, maybe through some inductor. Further I don't know where to go, because I don't know where this track goes out.?Please help, I want to fix it.
