Greetings to the group. After owning several 75A-4's over the years, and of course going through the sometimes troublesome modifications on certain units throughout the production run, I thought it would be fun to exercise our collective minds in discussing the various attributes to this fine receiver, both pro and con. This stems from recent comments made by a couple of our members here regarding comparisons between the A-4 and National variants. I intend to make this an A-4 only thread but comparisons if worthy are welcomed. Presently I have serial #1524 in my shop. It may become mine as the owner expresses no real desire to keep it as it won't see much use. As we go through the discussions, this receiver will be used as an example of current condition, performance grading, and repair/service bulletin application, and of course accepted modifications to insure the highest performance. I hope to use this thread as a tool for understanding to everyone interested in this fine design, but most importantly, for those not so well acquainted with the design and it's place in radio history. As a starter resource, the Collins Collectors Association maintains a deep historically correct database of information on the 75A-4. For those of you not so well informed on the subject, I advise you take time and read up on the background of it's design and production. This is a requisite study in the history of radio design advancement and should be respected as such in the premise of this discussion. Have fun, and let it rip! I look forward to the comments.