Spectracom have always seemed a bit "cautious" when it comes to releasing copies of the Pendulum Counter service manuals, I was sent a copy of the CNT90/91 manual when carrying out some repairs a few years ago but only after accepting a non disclosure agreement. Because of that I was quite surprised recently to find that Fluke have released the full service manual for many of their equivalents to the Pendulum counters, with these seeming to be identical to the pendulum originals but with name and model numbers changed. A similar situation exists for the Fluke and Pendulum user manuals but in this case both are widely available anyway. Recent searches have turned up service manuals for PM6680/CNT80, PM6681/CNT81, PM6685/CNT85, PM6690/CNT90. The only exception seems to be the CNT91, and as far as I can tell there never was a Fluke PM6691. The Pendulum CNT90/91 manual includes the revision A and B boards for the CNT90 as well as the later revision C used in the CNT91, whereas the Fluke PM6690 manual has no reference to the later board but does otherwise seem identical. Apologies if this is already common knowledge but I don't recall seeing any previous reference to it and thought it might of interest to other Pendulum users. Regards Nigel GM8PZR _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.