Galaxy DX99V
Talkback Feedback Fix
Modify audio circuitry by adding a 0.1uF ceramic capacitor between the “mic i/p” and “mic o/p” connections to earth on the echo/voice effect PCB, this will help to reduce RF feedback problems.
Add a 2.7KOhm resistor with a ferrite bead on it in series with the audio line after the mic gain control to reduce the audio level a touch, and adds even more filtering.
These mods seems to fix the RF feedback that plagues this chassis.
Channel Expansion
1) Open up your radio.
2) Find the small circuit board on the left of the radio.
3) Cut the green wire and tape it off.
4) There is an unplugged connector by this board….plug it in.
5) That’s it.!You now have 8 bands of 40 channels.25.165-28.755.
Tweaks
Lo Power - VR16
Hi Power - VR13
SSB Power - VR12
Modulation - VR14
Audio Limiter - TR53