Motorola Gm3688 Service Manual -

| Symptom | Likely Cause | Service Manual Reference | |---------|--------------|---------------------------| | No TX, but RX works | PA driver Q301 (2SC5101) shorted | Section 4.2.3 | | Low sensitivity | Q101 LNA (BFG591) damaged | Section 4.1.1 | | Distorted audio on TX | Microphone preamp capacitor C411 leaky | Section 3.4 | | Channel knob erratic | Control head encoder (mechanical wear) | Section 6 – Encoder part # | | PLL unlocks on high freqs | VCO varactor diode D202 failing | Section 2.3 |

The service manual is designed for qualified technicians and emphasizes: Motorola Gm3688 Service Manual - Facebook Motorola Gm3688 Service Manual

I should avoid being too technical for the general audience, but still provide enough detail to show the manual's contents. Mentioning things like block diagrams, exploded views, torque specifications for screws, and part numbers would be relevant. | Symptom | Likely Cause | Service Manual