Does anyone have a 301 that does not require all mic gain controls to be maxed out and close talk the mic to even get close to full output?
I have been struggling with this 301 since I got it trying to get enough modulation to get full output on SSB. On CW, full output is no problem. I thought maybe I had a defective LD3141, but every test I do tells me otherwise. The only thing that works is an outboard op-amp at 300x voltage gain driving the balanced modulator directly with 700-800 mv at full audio. I have built duplicates of the LD3141 on the breadboard with exactly the same gain as the original component. With about 2-3 mv into the LD3141 from a dynamic mic, I get between 150-200 mv out to the balanced modulator but I cannot find gain specs for the LD3141 to know if this is good. I do not want to condemn this component until I know better.
All the modulator diodes junction test ok and exhibit the correct Vf for a germanium diode. I do not see any indication that they were changed before I got it.
Carrier points have been verified to be correct, as well.
