TX audio is not loud enough, i.e. average fm deviation is too low. There is no conventional way to align it, because the V-8000 has no pot to adjust fm deviation.
First, you can increase the hole in the mic and esp. The hole of the plastic keypad inside the mic as K8DXN describes. But that is not enough.
FM deviation is set in IC 5, an 8-bit D/A converter. Because no software alignment is possible I decided to insert a pot to set the deviation.
- Find IC 5=M62363, 24pin smd D/A converter (see picture)
- Solder off pin 1 and pin 2
- Solder a 100k pot on jumper 2 (J2 in the picture), one end to pin 2 and the other at pin 6 (ground)
- Solder the free end of the pot to the place where pin 2 of IC 5 was
soldered on the board (pin 2 now soldered off)
- Connect free pin 1 of IC 5 with pin 12 of IC 5
- Adjust fm dev with the 100 k pot
- There is no more difference in fm dev between wide and narrow operation.