The Mackay 128-AY Receiver
Some years ago, I tried to find a manual for the Mackay 128-AY shipboard receiver. I was able to find a manual issued to the U.S. Coast Guard which covered nearly the same receiver, the 128-AZ, under a Coast Guard designation RC-123. The schematic diagram was originally separated into three pages, and the wiring diagram into two pages. Recently, through the kindness of David Sampson, I was loaned a complete manual for the Mackay 128AY, and I have uploaded it here. I have also included a high-resolution .JPG of both the complete schematic and of the wiring diagram. The files for the Coast Guard 128AZ are here also. Use what you need.