This modification applies to the line input of TRX2. If you don't use the line input, e.g digi modes, this modification is not needed.
The modification improves the line input performance when a sound card is used as a audio source.

Here are the modifications.
1. Line input gain adjusted by changing the value of R82 from 470k to 100k.
2. Full disconnection of the speech processor in line input mode by added JFET TR12.

Click here the modification schematics, including the detailed instructions (pdf)

Picture of the modification

Another view of the modification