John Ackermann N8UR said, in part, "The only hint I've found is that they were apparently widely used in US Air Force repair/calibration shops, and I suspect someone with the right contacts could find the manual through USAF sources."
John, If you can establish a military technical manual (TM) number for it, you can try public access to LOGSA Electronic TMs. The R-390 list on QTH has used this as a resource for a long time. Not all of it is public, though. Bill Hawkins _______________________________________________ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts