the wide band modification of IC-7300 by removing some of diodes on the diode matrix board (close to the big RENESAS chip see below) is going to open your RX and TX in few different ranges.
Most known modification article is by Marcus, PA2DB...
Open RX 0.030-74.8Mhz (REMOVE D416)
Open TX 0.1-74.8Mhz (REMOVE D422) (D419 is and must be in)
If you don't want to modify your radio for out of band TX operation then you can just open the TX for 60m band:
Only Open TX 60Mtr 5.255-5.405Mhz (REMOVE D405)
After flashing the updates, the mod remained there..."
Check at min 21:00 to see the diode matrix after the mod!"
Also I really like to recommending every time follow the instructions written very well below:
Some words of "wisdom" to read BEFORE you proceed to the mod:
Just like any other mods, beware that you do it on your risk and you loose the warranty!1. Check the radio to be disconnected from power supply
2. Please, use ESD discharge measures! No kidding, use ESD countermeasures both for your body and for the soldering station!
3. Use a lot of soldering flux! The diodes are very sensitive to high temperature and the solder Flux (I use GEL type) help in reducing the temperature for the areas not touched by the soldering station's tip.
4. Use 60/40 soldering alloy to reduce the melting point for the ROHS solders!
5. Use unsolder braid to clean the PCB pads!
6. Use a good soldering station!
7. Use good tweezers.
8. Use good magnifying glasses AND/OR microscope. The diodes are very very small.
I had some e-mails form a fellow ham who removed the D413 from error and the radio is not working on 6m band! He put the diode back but the radio remains without 6 m band.
I do not know if he fried the original diode but AFAIK, the diode matrix established the country version.
I suggest to put the diodes just as above and do a re-flash.
I just test to see if a downgrade to 1.12 (now I have 1.13) is possible and it is!
(Many thanks to Markus, PA2DB for his good job and hope it will help to some others.)
73 - Petr, OK1RP