To those who may also need this -- I've located a schematic for the version of the HQ-180A that uses the 80/40/20 power supply filter cap. The diagram was originally published in the Hammarlund "Issue 3" manual, dated September 1968. Download link: https://drive.google.com/open?id=1EVk0Vxg6RqZMUpx34sCFuIhNSkOZ2rwb 73, Steve, KW4H