I’d like to see more technical detail other than saying it doesn’t work.
Is that the wrong jack in the radio to use? Is it the wrong pin? How is it that it works for some people and yet not recommended by the manufacturer?
To give some technical context, the "key" line is brought out on both the 8 pin tuner jack and the 10 pin linear jack. The Yaesu term for a "key" line is "TX GND".
The 8 pin tuner TX GND and the 10 pin linear TX GND signals are schematically similar. Both are driven from the internal "TXB" signal and each has its own 2SD2403BY in an identical open collector configuration. They have similar heatsinking on the PCB as well.
What is ironic in relation to this thread is that the 8 pin tuner TX GND signal is better conditioned from an RF perspective than the 10 pin linear TX GND signal! The tuner TX GND signal includes a ferrite bead for RFI suppression and an additional bypass capacitor on the base of the open collector driver.
So with no additional data, I would sooner key the linear from the 8 pin tuner jack than the 10 pin linear jack as it is likely to be more RFI immune.
I see that there are two threads on this same topic (grrrr....), so I will cross post.
- Glenn W9IQ