Kenwood TH-D75 frequency expansion (MARS/CAP mod)

The TH-D75 has a resistor matrix consisting of 4 resistors (R1, R2, R3, R4) which are of SMD 0603 1k type. 2 of them (R1, R2) are accessible in an easy way and labeled on the top PCB in the lower left corner.

In the usual case it should be enough removing R1 (be careful) in order to open the TX range on a TH-D75E.

The „E2“ version (with maximal TX frequency range) looks in detail the following:

R1 removed
R2 installed
R3 installed
R4 removed

R3 and R4 (on the rear side of the PCB) should only be checked in seldom cases when just removing R1 doesn’t give the expected result.

In the E2 version all functions (e.g. Automatic Repeater Shift ARS) will remain – just the TX range is „open“.

As read in several articles in various forums for the TH-D75A removing R2 will expand the TX range. The default configuration of R3 and R4 for the American version is currently unknown.

An unimportant note: while trying different combinations R1 installed, R2 removed, R3 installed, R4 removed will result in a kind of Japanese version.

A photo of the rear side of the PCB in order to determine R3 and R4:

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Datum: Dienstag, 6. Februar 2024 18:24