Extended Transmit Frequency Modification

Yaesu Model VX-7R and FT-7900R

WARNING!

• It is illegal to transmit on any frequencies you are not authorize to by FCC.

• Modification voids manufacturers warranty. Proceed at your own risk.

Why Modify:

• To extend transmit frequencies beyond HAM band.

• Use same radio to communicate on other radio services you are authorized/licensed to.

Why NOT to Modify:

• Other than being authorize to transmit on frequencies other than HAM band (i.e. General Mobile Radio Service, Military  Affiliated Radio Service, Civil Air Patrol, etc), there's no reason to modify your Yaesu equipment and voids its manufacturers warranty.  

What's covered and what's not:

• This modification is specifically for Yaesu Model VX-7 and FT-7900. Though, most Yaesu VX and FT models (i.e. VX-8, VX-6, VX-5, FT-8900, FT-8800, FT-7800, etc) have similar circuitry and same procedure.

Procedure:

Model: FT-7900

1. Disconnects all connections from the main unit (i.e. power supply, antenna, etc) and detach front panel from the main unit.

2. Loosen and remove 8 screws securing top cover (Figure 1) then flip open the cover.

3. Unsolder/remove R1288, zero (0) Ohm Resistor a.k.a. Jumper Resistor, from the jumper array. R1288 is located left of microprocessor (M3826AMFA-201GP) and closest to the front panel (Figure 2a & 2b).

4. Clean area (Figure 3) using cue tip soak in alcohol or acetone (or flux remover.)

5. Replace top cover and secure it with the 8 screws.

6. Attach all connections and power up unit.

        NOTE: Upon initial power up (after modification), unit will perform system reset which erases all data stored in memory.

       Figure 1.               Figure 2a.              Figure 2b.                Figure 3.       

Model: VX-7

1. Detach battery from the main unit.

2. Using a Xacto knife or equivalent, remove the sticker seal/PCB cover and SU-1 module, if installed.

3. Locate jumper array (Figure 4).

4. Unsolder solder blob on jumper 4 & 5. Use of a solder wick is highly recommended and avoid solder sucker.

5. Clean area using cue tip soak in alcohol or acetone (or flux remover.)

6. Reinstall SU-1 (if available) and sticker seal/PCB cover then battery.

7. Perform system reset by press and hold "4", "BAND" and "V/M" keys then power button.

        NOTE: Performing system reset which erases all data stored in memory.

Figure 4.