Having had K3 for a while now I was interested to see the arrival of the "upgraded" model the K3S. While it is possible to buy the modules to upgrade a K3 to a K3S having done the calculations it was cheaper to buy a K3S in kit form and transfer the "option" modules across.
The K3S/100 kit, with the new 100W FET PA module was ordered.
It all went together easily enough despite some issues with K3 photos/figures appearing in the K3S manual (eg Figure 91). It powered up fine and the VCO passed self test, so time to hook up an antenna. Nothing could be heard despite putting the RX on the TX7EU pileup. As a check an HP signal generator was hooked up to the antenna port. It couldn’t hear -50dBm. Neither could this level be heard through the rx in port or the Xverter port. The radio was dismantled, all connectors checked, EEinit done, no improvement.
Time for more coffee, during which an inspiration. When I put the subrx into the k3 I remembered I had to remove a link in the KRX3 back connector. (J64A) So I searched the K3S manual. It appeared not to need the link as it was not shown in "Figure 31. RF Board Partially Assembled." or on the photo of the main rf board on Page a-14 or on "Figure 94. Installing the KBPF3A Option Board." BUT I noticed a link still shown on the legend on the PCB and its removal is still shown in fig44 of E740126A installing the KRX3A subrx. "Nothing ventured nothing gained", so I stuck a resistor lead in the W4 link and the K3S burst into life. Sensitivity returned and the K3S was back to full health. Perhaps someone should have checked that when the K3 manual was converted to a K3 it was correct.
The other issue was the top left screw holding the bezel to the font panel would not bind. Close examination revealed that there was insufficient threading in the hole. After talking to Elecraft Support they shipped a replacement front panel, which arrived three days later and resolved the issue.