Got a new freqency counter, the Fluke PM6690. First, it is also about Spectracom/Pendulum CNT-90 and also about Tektronix FCA3000. These counters are actually relabeled Pendulum CNT-90.
It needs only 100µs “gate” time for 1Hz and 100ms for 1mHz resolution. Can measure 10MHz with 10µHz accuracy.
Have opened it, resoldered faulty backlight, cleaned and closed back again.
Came with older firmware, Pendulum provides version 1.28, so did the update.
Last updated on 2023:02:23 at 02:10 UTC