Yaesu: FTM-500DR - American model PCB differences for MARS mod

[eraser928]

Thank you for this thread!

The mod worked on the 4E board (bought May 2024 at DX Engineering) by removing the tiny diode in the pink circle in the OP's picture. We did not try the shorting resistor method.

 

[KE9ARJ]

I preformed the mod on my 500dr with a serial number beginning with 4F. The board appeared to have a similar layout to the 4D. I simple removed the smaller diode, nothing fancy, just snipped it out and verified that the traces were no longer connected with any remaining solder. After reassembly the radio started up in its factory form. I could not read from the SD card. Simply format your SD card (save your data else where first) and write to the SD from the radio menu. I then popped out the SD card and placed it in the PC and saved my previous settings on the card. The radio was able to read from the card at this point. Very simple mod. All is working as it was prior to modding with the added TX range.

 

[AK9R]

I preformed the mod on my 500dr with a serial number beginning with 4F. The board appeared to have a similar layout to the 4D.

The first two digits in a Yaesu serial number indicate the year and month of manufacture.

4 indicates 2024. The month code starts with C for January, so D is February and F is April.

 

[pramodn]

Hi All, Pramod (VU3UZJ) here. I recently purchased a Yaesu FTM500DR(4H) from Japan and attempted the MARS mod. Unfortunately, I removed the 0-ohm resistor (highlighted in the pink circle) without seeing this thread beforehand, and now my TX is locked. Upon further inspection, I noticed a short in the area highlighted in the orange circle. I would appreciate any guidance on whether any additional changes are required to unlock the TX for use outside the Ham bands.

 

[KD7RJC]

Hi All, Pramod (VU3UZJ) here. I recently purchased a Yaesu FTM500DR(4H) from Japan and attempted the MARS mod. Unfortunately, I removed the 0-ohm resistor (highlighted in the pink circle) without seeing this thread beforehand, and now my TX is locked. Upon further inspection, I noticed a short in the area highlighted in the orange circle. I would appreciate any guidance on whether any additional changes are required to unlock the TX for use outside the Ham bands.

I thought there was a button combination for resetting after modding but it's been several months and I can't remember with certainly.

 

[pramodn]

I thought there was a button combination for resetting after modding but it's been several months and I can't remember with certainly.

Could you please assist me if you recall the button combination? I attempted to restore my radio to factory default settings using menu option number 127. However I am unable to TX outside ham band.