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FT-7900R MARS Mod | Radioaficion Ham Radio

FT-7900R MARS Mod

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Yaesu FT-7900R MARS Mod

I decided to post it so owners of an FT-7900 would have a mod file specifically for the FT-7900 and not have to spend several hours of looking and getting the same results I did.

Disclaimer


I do not claim that this mod will work for you. It worked only for me on the one radio I own. If you are unsure of what you are doing, DO NOT ATTEMPT THIS MOD! You make the mod described at your own risk and I cannot be held responsible in any way for how this mod will work on your radio.

Remember, it is against the law to use this radio on any frequency other than those authorized by your class of license. This radio is NOT FCC type accepted for any radio service other than the Amateur Radio service.

Steps for making this mod. I had to use a large magnifying glass the whole time I was working on this radio. These parts are extremely small so be really careful!

Make a backup of your programming before doing the mod.

You will loose all previous programming when you turn the radio on the first time after making the mod and you will need to reprogram your radio.

DISCONNECT THE POWER CORD!

With the radio facing toward you, remove the eight screws holding the top cover, lift the cover off and disconnect the speaker.

Yaesu FT-7900R MARS Mod


With the radio still facing toward you, look in the front left hand corner (corner closest to your body), you will see the microprocessor.

Yaesu FT-7900R MARS Mod


To the left of the processor, there will a row of eight (8)jumper solder lands on the main board

Yaesu FT-7900R MARS Mod


With the radio still facing toward you, there will be two extremely small, black jumpers soldered across onto the main board. The jumper that must be removed is the jumper closest to the front of the radio. The blue arrow points to the correct jumper.

Yaesu FT-7900R MARS Mod


I used a 7.5 watt pencil iron from Radio Shack with the tip shaved to a very fine point and it was still about 4X larger than I needed. After I un-soldered the ground side of the jumper and then proceeded to accidentally break the trace on the high side of the jumper, the thought occurred to me that it probably would have been easier to just cut the trace on the high side of the jumper! That will be up to you and I have not specifically tried doing it that and leaving the jumper soldered to the board.

Yaesu FT-7900R MARS Mod


Reassemble the radio, hookup power, and turn on the radio. The display will momentarily totally light up as the radio performs an automatic CPU and memory reset. When a frequency is displayed, hook the radio to a dummy load and check your transmit range. Reprogram your radio accordingly. You have now completed the extended transmit frequency range for the FT-7900.

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