I've had a couple ranger made radios with the speaker jack issue you describe. You can clean those contacts and find flux being the issue. The sra-198 is known for that, you have to almost eat the mic when talking into it. For that reason I prefer either the 636L or Telex rk56 over the 198. I think you'll find the bad factory tune to be another commonality among the rangers.Defects I have found so far:
- Stock SRA-198 microphone attenuates modulation significantly
- out-of-the-box SSB power far below 12w
- 3mm external speaker connector does not return to open after 3mm speaker connection is removed. No audio until connector is then re-inserted part way, then removed.
Years back I'd use a flat thin blade screwdriver covered with a couple wraps of tape and worked ok and without scratching the faceplate. My wife has a thin rubber mat that's for gripping jar lids and works great, and it's great for gripping knobs to pull them right off too. I used hers a few times she eventually just bought me my own.figured out the knob removal