Hi there. Bear with me, as I am quite new to all of this.
I've acquired a second-hand Superstar 121 radio, (PCB EPT120113Z). While AM TX audio works perfectly fine, FM TX audio is pretty much non-existant.
While using a spectrum analyzer, I adjusted the FM deviation (VR5) with no change. Using a nearby SDR receiver, with the volume and gain at its highest, the FM TX audio is extraordinarily faint.
Upon inspecting the radio, it's been "worked on." TR32 AMC limiter is gone, J4 clipped(?), R205, R206 clipped, orange wire soldered to PCB component side of D84 (going to RF gain?).
Wondering if someone can guide me into next steps/direction in troubleshooting the FM TX audio issue?
Thank you!
I've acquired a second-hand Superstar 121 radio, (PCB EPT120113Z). While AM TX audio works perfectly fine, FM TX audio is pretty much non-existant.
While using a spectrum analyzer, I adjusted the FM deviation (VR5) with no change. Using a nearby SDR receiver, with the volume and gain at its highest, the FM TX audio is extraordinarily faint.
Upon inspecting the radio, it's been "worked on." TR32 AMC limiter is gone, J4 clipped(?), R205, R206 clipped, orange wire soldered to PCB component side of D84 (going to RF gain?).
Wondering if someone can guide me into next steps/direction in troubleshooting the FM TX audio issue?
Thank you!