CAUTION: Be certain to observe Anti-Stat precautions for an ESD-Safe work area.
- Remove the bottom cover of the IC-746Pro.
- Remove all cables and connectors and from the Main Unit PC bd.
- Remove all screws from the Main Unit PC Board, while noting in particular the following three screws:
- Remove the machine screw on IC1240, which bonds the heat sink tab to the cast metal chassis;
- Remove the screw from the rear panel to the plastic ALC and SEND connector housing; and
- Pay attention to the center PC bd screw which holds a grounding spring contact against the underside of the metal shielded sub-assembly.
- Change R1080 from 100K ohm to 22K ohm. R1080 is located on the bottom side of the Main Unit PC Board, next to IC1080, from pin 3 to C1080 (+).
See Service Manual Figure 9-9, Main Unit Bottom View, Page 9-8
See Service Manual Schematic Main Unit(1) Page/Figure 12-3
Alternatively, place a 30K in parallel with R1080, ~22K net value.
Preferably use a surface mount resistor of the same size, or a 1/16 watt discrete resistor, using a surface mount tip, ESD protected soldering iron at approximately 650 Deg F.
This modification raises the SSB Monitor level only, and provides approximately +9dB of additional gain. Adequate SSB Monitor volume can now be achieved when the Monitor Menu is set to ~90% without boosting the AF Gain setting.