[Elecraft] KAT100: No SWR Indication

[Jonathan Taylor, K1RFD]

After working OK for several years, my KAT100 no longer indicates SWR, nor
does it tune properly.

When used with my K2/100, in ATU Auto mode, with the TUNE button, the
KAT100 starts finding a match as expected.  However, none of the SWR LEDs
illuminate, and the K2 display indicates 1.0-1 SWR during the entire
search.  I am not at all convinced that it has found a good match once the
tuning sequence completes.  An SWR bridge placed between the K2 and the
KAT often shows a poor match after tuning.

I suspect a problem in the KAT's SWR bridge, but does anyone have specific
troubleshooting advice?

Thanks!