Replacing FDT86256 with BS170

[YS1RS]

Guys, a quick simple question here:
Can I replace the burned out FDT86256 (not available in my country) with the most common BS170 (plenty availability here)?
Do I have to do any configuration, any jumper to mod or anything to do this?
Or is just a simple thing as first remove the old FDT86256, clean well the area and just install the new BS170?

This will be done in a brand new Hi Bands RF Board.
The culprit... A battery pack providing 16 volts DC to the radio instead of a Max 13.8 VDC.

I know I have to run the filter adjustment to avoid interference if I do the change. But the question is if I have to do any jumper or something to the board or just remove the 86256 and drop in the new BS170.

Please let me know. Very thankful in advance.

Thanks.

73
Rob
YS1RS

[YS1RS]

Yes, you may replace the FDT86256 with the BS170 but the filters have been carefully calculated in the high bands board for the FDT86256, and not for the BS170 so, it is not advisable.
I will try to keep using the FDT86256. Sure that is the one that failed in your RF board.
Try to order replacements from Mouser, to make sure you obtain good quality ones. Order a few to make it worth it as shipping to your country sure is expensive.
Also, make sure you do all future alignments using only the USB 5.0 VDC. as input and not 12 Volts or more, cause the threshold for failure during adjustment is narrow with higher voltage, and you may blow more FDT86256s in the process.
If you do the alignment with only 5.0 VDC, your FET will have room to resist any differences while you obtain the best results in efficiency, and also in obtaining the closest to 5W output.

If you purchased locally your BS170s, keep them as spare for your Low Band (tr)uSDX. you never know when could these be handy for your Lo Band RF Board.

Best and good luck!

Rob